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    //! HTTP status codes
    //!
    //! This module contains HTTP-status code related structs an errors. The main
    //! type in this module is `StatusCode` which is not intended to be used through
    //! this module but rather the `http::StatusCode` type.
    //!
    //! # Examples
    //!
    //! ```
    //! use http::StatusCode;
    //!
    //! assert_eq!(StatusCode::from_u16(200).unwrap(), StatusCode::OK);
    //! assert_eq!(StatusCode::NOT_FOUND, 404);
    //! assert!(StatusCode::OK.is_success());
    //! ```

    use std::convert::TryFrom;
    use std::num::NonZeroU16;
    use std::error::Error;
    use std::fmt;
    use std::str::FromStr;

    /// An HTTP status code (`status-code` in RFC 7230 et al.).
    ///
    /// Constants are provided for known status codes, including those in the IANA
    /// [HTTP Status Code Registry](
    /// https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml).
    ///
    /// Status code values in the range 100-999 (inclusive) are supported by this
    /// type. Values in the range 100-599 are semantically classified by the most
    /// significant digit. See [`StatusCode::is_success`], etc. Values above 599
    /// are unclassified but allowed for legacy compatibility, though their use is
    /// discouraged. Applications may interpret such values as protocol errors.
    ///
    /// # Examples
    ///
    /// ```
    /// use http::StatusCode;
    ///
    /// assert_eq!(StatusCode::from_u16(200).unwrap(), StatusCode::OK);
    /// assert_eq!(StatusCode::NOT_FOUND.as_u16(), 404);
    /// assert!(StatusCode::OK.is_success());
    /// ```
    #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
    pub struct StatusCode(NonZeroU16);

    /// A possible error value when converting a `StatusCode` from a `u16` or `&str`
    ///
    /// This error indicates that the supplied input was not a valid number, was less
    /// than 100, or was greater than 999.
    pub struct InvalidStatusCode {
        _priv: (),
    }

    impl StatusCode {
        /// Converts a u16 to a status code.
        ///
        /// The function validates the correctness of the supplied u16. It must be
        /// greater or equal to 100 and less than 1000.
        ///
        /// # Example
        ///
        /// ```
        /// use http::StatusCode;
        ///
        /// let ok = StatusCode::from_u16(200).unwrap();
        /// assert_eq!(ok, StatusCode::OK);
        ///
        /// let err = StatusCode::from_u16(99);
        /// assert!(err.is_err());
        /// ```
        #[inline]
        pub fn from_u16(src: u16) -> Result<StatusCode, InvalidStatusCode> {
            if src < 100 || src >= 1000 {
                return Err(InvalidStatusCode::new());
            }

            NonZeroU16::new(src)
                .map(StatusCode)
                .ok_or_else(InvalidStatusCode::new)
        }

        /// Converts a &[u8] to a status code
        pub fn from_bytes(src: &[u8]) -> Result<StatusCode, InvalidStatusCode> {
            if src.len() != 3 {
                return Err(InvalidStatusCode::new());
            }

            let a = src[0].wrapping_sub(b'0') as u16;
            let b = src[1].wrapping_sub(b'0') as u16;
            let c = src[2].wrapping_sub(b'0') as u16;

            if a == 0 || a > 9 || b > 9 || c > 9 {
                return Err(InvalidStatusCode::new());
            }

            let status = (a * 100) + (b * 10) + c;
            NonZeroU16::new(status)
                .map(StatusCode)
                .ok_or_else(InvalidStatusCode::new)
        }

        /// Returns the `u16` corresponding to this `StatusCode`.
        ///
        /// # Note
        ///
        /// This is the same as the `From<StatusCode>` implementation, but
        /// included as an inherent method because that implementation doesn't
        /// appear in rustdocs, as well as a way to force the type instead of
        /// relying on inference.
        ///
        /// # Example
        ///
        /// ```
        /// let status = http::StatusCode::OK;
        /// assert_eq!(status.as_u16(), 200);
        /// ```
        #[inline]
        pub fn as_u16(&self) -> u16 {
            (*self).into()
        }

        /// Returns a &str representation of the `StatusCode`
        ///
        /// The return value only includes a numerical representation of the
        /// status code. The canonical reason is not included.
        ///
        /// # Example
        ///
        /// ```
        /// let status = http::StatusCode::OK;
        /// assert_eq!(status.as_str(), "200");
        /// ```
        #[inline]
        pub fn as_str(&self) -> &str {
            let offset = (self.0.get() - 100) as usize;
            let offset = offset * 3;

            // Invariant: self has checked range [100, 999] and CODE_DIGITS is
            // ASCII-only, of length 900 * 3 = 2700 bytes

            #[cfg(debug_assertions)]
            { &CODE_DIGITS[offset..offset+3] }

            #[cfg(not(debug_assertions))]
            unsafe { CODE_DIGITS.get_unchecked(offset..offset+3) }
        }

        /// Get the standardised `reason-phrase` for this status code.
        ///
        /// This is mostly here for servers writing responses, but could potentially have application
        /// at other times.
        ///
        /// The reason phrase is defined as being exclusively for human readers. You should avoid
        /// deriving any meaning from it at all costs.
        ///
        /// Bear in mind also that in HTTP/2.0 and HTTP/3.0 the reason phrase is abolished from
        /// transmission, and so this canonical reason phrase really is the only reason phrase you’ll
        /// find.
        ///
        /// # Example
        ///
        /// ```
        /// let status = http::StatusCode::OK;
        /// assert_eq!(status.canonical_reason(), Some("OK"));
        /// ```
        pub fn canonical_reason(&self) -> Option<&'static str> {
            canonical_reason(self.0.get())
        }

        /// Check if status is within 100-199.
        #[inline]
        pub fn is_informational(&self) -> bool {
            200 > self.0.get() && self.0.get() >= 100
        }

        /// Check if status is within 200-299.
        #[inline]
        pub fn is_success(&self) -> bool {
            300 > self.0.get() && self.0.get() >= 200
        }

        /// Check if status is within 300-399.
        #[inline]
        pub fn is_redirection(&self) -> bool {
            400 > self.0.get() && self.0.get() >= 300
        }

        /// Check if status is within 400-499.
        #[inline]
        pub fn is_client_error(&self) -> bool {
            500 > self.0.get() && self.0.get() >= 400
        }

        /// Check if status is within 500-599.
        #[inline]
        pub fn is_server_error(&self) -> bool {
            600 > self.0.get() && self.0.get() >= 500
        }
    }

    impl fmt::Debug for StatusCode {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            fmt::Debug::fmt(&self.0, f)
        }
    }

    /// Formats the status code, *including* the canonical reason.
    ///
    /// # Example
    ///
    /// ```
    /// # use http::StatusCode;
    /// assert_eq!(format!("{}", StatusCode::OK), "200 OK");
    /// ```
    impl fmt::Display for StatusCode {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            write!(
                f,
                "{} {}",
                u16::from(*self),
                self.canonical_reason().unwrap_or("<unknown status code>")
            )
        }
    }

    impl Default for StatusCode {
        #[inline]
        fn default() -> StatusCode {
            StatusCode::OK
        }
    }

    impl PartialEq<u16> for StatusCode {
        #[inline]
        fn eq(&self, other: &u16) -> bool {
            self.as_u16() == *other
        }
    }

    impl PartialEq<StatusCode> for u16 {
        #[inline]
        fn eq(&self, other: &StatusCode) -> bool {
            *self == other.as_u16()
        }
    }

    impl From<StatusCode> for u16 {
        #[inline]
        fn from(status: StatusCode) -> u16 {
            status.0.get()
        }
    }

    impl FromStr for StatusCode {
        type Err = InvalidStatusCode;

        fn from_str(s: &str) -> Result<StatusCode, InvalidStatusCode> {
            StatusCode::from_bytes(s.as_ref())
        }
    }

    impl<'a> From<&'a StatusCode> for StatusCode {
        #[inline]
        fn from(t: &'a StatusCode) -> Self {
            t.clone()
        }
    }

    impl<'a> TryFrom<&'a [u8]> for StatusCode {
        type Error = InvalidStatusCode;

        #[inline]
        fn try_from(t: &'a [u8]) -> Result<Self, Self::Error> {
            StatusCode::from_bytes(t)
        }
    }

    impl<'a> TryFrom<&'a str> for StatusCode {
        type Error = InvalidStatusCode;

        #[inline]
        fn try_from(t: &'a str) -> Result<Self, Self::Error> {
            t.parse()
        }
    }

    impl TryFrom<u16> for StatusCode {
        type Error = InvalidStatusCode;

        #[inline]
        fn try_from(t: u16) -> Result<Self, Self::Error> {
            StatusCode::from_u16(t)
        }
    }

    macro_rules! status_codes {
        (
            $(
                $(#[$docs:meta])*
                ($num:expr, $konst:ident, $phrase:expr);
            )+
        ) => {
            impl StatusCode {
            $(
                $(#[$docs])*
                pub const $konst: StatusCode = StatusCode(unsafe { NonZeroU16::new_unchecked($num) });
            )+

            }

            fn canonical_reason(num: u16) -> Option<&'static str> {
                match num {
                    $(
                    $num => Some($phrase),
                    )+
                    _ => None
                }
            }
        }
    }

    status_codes! {
        /// 100 Continue
        /// [[RFC7231, Section 6.2.1](https://tools.ietf.org/html/rfc7231#section-6.2.1)]
        (100, CONTINUE, "Continue");
        /// 101 Switching Protocols
        /// [[RFC7231, Section 6.2.2](https://tools.ietf.org/html/rfc7231#section-6.2.2)]
        (101, SWITCHING_PROTOCOLS, "Switching Protocols");
        /// 102 Processing
        /// [[RFC2518](https://tools.ietf.org/html/rfc2518)]
        (102, PROCESSING, "Processing");

        /// 200 OK
        /// [[RFC7231, Section 6.3.1](https://tools.ietf.org/html/rfc7231#section-6.3.1)]
        (200, OK, "OK");
        /// 201 Created
        /// [[RFC7231, Section 6.3.2](https://tools.ietf.org/html/rfc7231#section-6.3.2)]
        (201, CREATED, "Created");
        /// 202 Accepted
        /// [[RFC7231, Section 6.3.3](https://tools.ietf.org/html/rfc7231#section-6.3.3)]
        (202, ACCEPTED, "Accepted");
        /// 203 Non-Authoritative Information
        /// [[RFC7231, Section 6.3.4](https://tools.ietf.org/html/rfc7231#section-6.3.4)]
        (203, NON_AUTHORITATIVE_INFORMATION, "Non Authoritative Information");
        /// 204 No Content
        /// [[RFC7231, Section 6.3.5](https://tools.ietf.org/html/rfc7231#section-6.3.5)]
        (204, NO_CONTENT, "No Content");
        /// 205 Reset Content
        /// [[RFC7231, Section 6.3.6](https://tools.ietf.org/html/rfc7231#section-6.3.6)]
        (205, RESET_CONTENT, "Reset Content");
        /// 206 Partial Content
        /// [[RFC7233, Section 4.1](https://tools.ietf.org/html/rfc7233#section-4.1)]
        (206, PARTIAL_CONTENT, "Partial Content");
        /// 207 Multi-Status
        /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
        (207, MULTI_STATUS, "Multi-Status");
        /// 208 Already Reported
        /// [[RFC5842](https://tools.ietf.org/html/rfc5842)]
        (208, ALREADY_REPORTED, "Already Reported");

        /// 226 IM Used
        /// [[RFC3229](https://tools.ietf.org/html/rfc3229)]
        (226, IM_USED, "IM Used");

        /// 300 Multiple Choices
        /// [[RFC7231, Section 6.4.1](https://tools.ietf.org/html/rfc7231#section-6.4.1)]
        (300, MULTIPLE_CHOICES, "Multiple Choices");
        /// 301 Moved Permanently
        /// [[RFC7231, Section 6.4.2](https://tools.ietf.org/html/rfc7231#section-6.4.2)]
        (301, MOVED_PERMANENTLY, "Moved Permanently");
        /// 302 Found
        /// [[RFC7231, Section 6.4.3](https://tools.ietf.org/html/rfc7231#section-6.4.3)]
        (302, FOUND, "Found");
        /// 303 See Other
        /// [[RFC7231, Section 6.4.4](https://tools.ietf.org/html/rfc7231#section-6.4.4)]
        (303, SEE_OTHER, "See Other");
        /// 304 Not Modified
        /// [[RFC7232, Section 4.1](https://tools.ietf.org/html/rfc7232#section-4.1)]
        (304, NOT_MODIFIED, "Not Modified");
        /// 305 Use Proxy
        /// [[RFC7231, Section 6.4.5](https://tools.ietf.org/html/rfc7231#section-6.4.5)]
        (305, USE_PROXY, "Use Proxy");
        /// 307 Temporary Redirect
        /// [[RFC7231, Section 6.4.7](https://tools.ietf.org/html/rfc7231#section-6.4.7)]
        (307, TEMPORARY_REDIRECT, "Temporary Redirect");
        /// 308 Permanent Redirect
        /// [[RFC7238](https://tools.ietf.org/html/rfc7238)]
        (308, PERMANENT_REDIRECT, "Permanent Redirect");

        /// 400 Bad Request
        /// [[RFC7231, Section 6.5.1](https://tools.ietf.org/html/rfc7231#section-6.5.1)]
        (400, BAD_REQUEST, "Bad Request");
        /// 401 Unauthorized
        /// [[RFC7235, Section 3.1](https://tools.ietf.org/html/rfc7235#section-3.1)]
        (401, UNAUTHORIZED, "Unauthorized");
        /// 402 Payment Required
        /// [[RFC7231, Section 6.5.2](https://tools.ietf.org/html/rfc7231#section-6.5.2)]
        (402, PAYMENT_REQUIRED, "Payment Required");
        /// 403 Forbidden
        /// [[RFC7231, Section 6.5.3](https://tools.ietf.org/html/rfc7231#section-6.5.3)]
        (403, FORBIDDEN, "Forbidden");
        /// 404 Not Found
        /// [[RFC7231, Section 6.5.4](https://tools.ietf.org/html/rfc7231#section-6.5.4)]
        (404, NOT_FOUND, "Not Found");
        /// 405 Method Not Allowed
        /// [[RFC7231, Section 6.5.5](https://tools.ietf.org/html/rfc7231#section-6.5.5)]
        (405, METHOD_NOT_ALLOWED, "Method Not Allowed");
        /// 406 Not Acceptable
        /// [[RFC7231, Section 6.5.6](https://tools.ietf.org/html/rfc7231#section-6.5.6)]
        (406, NOT_ACCEPTABLE, "Not Acceptable");
        /// 407 Proxy Authentication Required
        /// [[RFC7235, Section 3.2](https://tools.ietf.org/html/rfc7235#section-3.2)]
        (407, PROXY_AUTHENTICATION_REQUIRED, "Proxy Authentication Required");
        /// 408 Request Timeout
        /// [[RFC7231, Section 6.5.7](https://tools.ietf.org/html/rfc7231#section-6.5.7)]
        (408, REQUEST_TIMEOUT, "Request Timeout");
        /// 409 Conflict
        /// [[RFC7231, Section 6.5.8](https://tools.ietf.org/html/rfc7231#section-6.5.8)]
        (409, CONFLICT, "Conflict");
        /// 410 Gone
        /// [[RFC7231, Section 6.5.9](https://tools.ietf.org/html/rfc7231#section-6.5.9)]
        (410, GONE, "Gone");
        /// 411 Length Required
        /// [[RFC7231, Section 6.5.10](https://tools.ietf.org/html/rfc7231#section-6.5.10)]
        (411, LENGTH_REQUIRED, "Length Required");
        /// 412 Precondition Failed
        /// [[RFC7232, Section 4.2](https://tools.ietf.org/html/rfc7232#section-4.2)]
        (412, PRECONDITION_FAILED, "Precondition Failed");
        /// 413 Payload Too Large
        /// [[RFC7231, Section 6.5.11](https://tools.ietf.org/html/rfc7231#section-6.5.11)]
        (413, PAYLOAD_TOO_LARGE, "Payload Too Large");
        /// 414 URI Too Long
        /// [[RFC7231, Section 6.5.12](https://tools.ietf.org/html/rfc7231#section-6.5.12)]
        (414, URI_TOO_LONG, "URI Too Long");
        /// 415 Unsupported Media Type
        /// [[RFC7231, Section 6.5.13](https://tools.ietf.org/html/rfc7231#section-6.5.13)]
        (415, UNSUPPORTED_MEDIA_TYPE, "Unsupported Media Type");
        /// 416 Range Not Satisfiable
        /// [[RFC7233, Section 4.4](https://tools.ietf.org/html/rfc7233#section-4.4)]
        (416, RANGE_NOT_SATISFIABLE, "Range Not Satisfiable");
        /// 417 Expectation Failed
        /// [[RFC7231, Section 6.5.14](https://tools.ietf.org/html/rfc7231#section-6.5.14)]
        (417, EXPECTATION_FAILED, "Expectation Failed");
        /// 418 I'm a teapot
        /// [curiously not registered by IANA but [RFC2324](https://tools.ietf.org/html/rfc2324)]
        (418, IM_A_TEAPOT, "I'm a teapot");

        /// 421 Misdirected Request
        /// [RFC7540, Section 9.1.2](http://tools.ietf.org/html/rfc7540#section-9.1.2)
        (421, MISDIRECTED_REQUEST, "Misdirected Request");
        /// 422 Unprocessable Entity
        /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
        (422, UNPROCESSABLE_ENTITY, "Unprocessable Entity");
        /// 423 Locked
        /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
        (423, LOCKED, "Locked");
        /// 424 Failed Dependency
        /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
        (424, FAILED_DEPENDENCY, "Failed Dependency");

        /// 426 Upgrade Required
        /// [[RFC7231, Section 6.5.15](https://tools.ietf.org/html/rfc7231#section-6.5.15)]
        (426, UPGRADE_REQUIRED, "Upgrade Required");

        /// 428 Precondition Required
        /// [[RFC6585](https://tools.ietf.org/html/rfc6585)]
        (428, PRECONDITION_REQUIRED, "Precondition Required");
        /// 429 Too Many Requests
        /// [[RFC6585](https://tools.ietf.org/html/rfc6585)]
        (429, TOO_MANY_REQUESTS, "Too Many Requests");

        /// 431 Request Header Fields Too Large
        /// [[RFC6585](https://tools.ietf.org/html/rfc6585)]
        (431, REQUEST_HEADER_FIELDS_TOO_LARGE, "Request Header Fields Too Large");

        /// 451 Unavailable For Legal Reasons
        /// [[RFC7725](http://tools.ietf.org/html/rfc7725)]
        (451, UNAVAILABLE_FOR_LEGAL_REASONS, "Unavailable For Legal Reasons");

        /// 500 Internal Server Error
        /// [[RFC7231, Section 6.6.1](https://tools.ietf.org/html/rfc7231#section-6.6.1)]
        (500, INTERNAL_SERVER_ERROR, "Internal Server Error");
        /// 501 Not Implemented
        /// [[RFC7231, Section 6.6.2](https://tools.ietf.org/html/rfc7231#section-6.6.2)]
        (501, NOT_IMPLEMENTED, "Not Implemented");
        /// 502 Bad Gateway
        /// [[RFC7231, Section 6.6.3](https://tools.ietf.org/html/rfc7231#section-6.6.3)]
        (502, BAD_GATEWAY, "Bad Gateway");
        /// 503 Service Unavailable
        /// [[RFC7231, Section 6.6.4](https://tools.ietf.org/html/rfc7231#section-6.6.4)]
        (503, SERVICE_UNAVAILABLE, "Service Unavailable");
        /// 504 Gateway Timeout
        /// [[RFC7231, Section 6.6.5](https://tools.ietf.org/html/rfc7231#section-6.6.5)]
        (504, GATEWAY_TIMEOUT, "Gateway Timeout");
        /// 505 HTTP Version Not Supported
        /// [[RFC7231, Section 6.6.6](https://tools.ietf.org/html/rfc7231#section-6.6.6)]
        (505, HTTP_VERSION_NOT_SUPPORTED, "HTTP Version Not Supported");
        /// 506 Variant Also Negotiates
        /// [[RFC2295](https://tools.ietf.org/html/rfc2295)]
        (506, VARIANT_ALSO_NEGOTIATES, "Variant Also Negotiates");
        /// 507 Insufficient Storage
        /// [[RFC4918](https://tools.ietf.org/html/rfc4918)]
        (507, INSUFFICIENT_STORAGE, "Insufficient Storage");
        /// 508 Loop Detected
        /// [[RFC5842](https://tools.ietf.org/html/rfc5842)]
        (508, LOOP_DETECTED, "Loop Detected");

        /// 510 Not Extended
        /// [[RFC2774](https://tools.ietf.org/html/rfc2774)]
        (510, NOT_EXTENDED, "Not Extended");
        /// 511 Network Authentication Required
        /// [[RFC6585](https://tools.ietf.org/html/rfc6585)]
        (511, NETWORK_AUTHENTICATION_REQUIRED, "Network Authentication Required");
    }

    impl InvalidStatusCode {
        fn new() -> InvalidStatusCode {
            InvalidStatusCode {
                _priv: (),
            }
        }
    }

    impl fmt::Debug for InvalidStatusCode {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            f.debug_struct("InvalidStatusCode")
                // skip _priv noise
                .finish()
        }
    }

    impl fmt::Display for InvalidStatusCode {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            f.write_str("invalid status code")
        }
    }

    impl Error for InvalidStatusCode {}

    // A string of packed 3-ASCII-digit status code values for the supported range
    // of [100, 999] (900 codes, 2700 bytes).
    const CODE_DIGITS: &'static str = "\
    100101102103104105106107108109110111112113114115116117118119\
    120121122123124125126127128129130131132133134135136137138139\
    140141142143144145146147148149150151152153154155156157158159\
    160161162163164165166167168169170171172173174175176177178179\
    180181182183184185186187188189190191192193194195196197198199\
    200201202203204205206207208209210211212213214215216217218219\
    220221222223224225226227228229230231232233234235236237238239\
    240241242243244245246247248249250251252253254255256257258259\
    260261262263264265266267268269270271272273274275276277278279\
    280281282283284285286287288289290291292293294295296297298299\
    300301302303304305306307308309310311312313314315316317318319\
    320321322323324325326327328329330331332333334335336337338339\
    340341342343344345346347348349350351352353354355356357358359\
    360361362363364365366367368369370371372373374375376377378379\
    380381382383384385386387388389390391392393394395396397398399\
    400401402403404405406407408409410411412413414415416417418419\
    420421422423424425426427428429430431432433434435436437438439\
    440441442443444445446447448449450451452453454455456457458459\
    460461462463464465466467468469470471472473474475476477478479\
    480481482483484485486487488489490491492493494495496497498499\
    500501502503504505506507508509510511512513514515516517518519\
    520521522523524525526527528529530531532533534535536537538539\
    540541542543544545546547548549550551552553554555556557558559\
    560561562563564565566567568569570571572573574575576577578579\
    580581582583584585586587588589590591592593594595596597598599\
    600601602603604605606607608609610611612613614615616617618619\
    620621622623624625626627628629630631632633634635636637638639\
    640641642643644645646647648649650651652653654655656657658659\
    660661662663664665666667668669670671672673674675676677678679\
    680681682683684685686687688689690691692693694695696697698699\
    700701702703704705706707708709710711712713714715716717718719\
    720721722723724725726727728729730731732733734735736737738739\
    740741742743744745746747748749750751752753754755756757758759\
    760761762763764765766767768769770771772773774775776777778779\
    780781782783784785786787788789790791792793794795796797798799\
    800801802803804805806807808809810811812813814815816817818819\
    820821822823824825826827828829830831832833834835836837838839\
    840841842843844845846847848849850851852853854855856857858859\
    860861862863864865866867868869870871872873874875876877878879\
    880881882883884885886887888889890891892893894895896897898899\
    900901902903904905906907908909910911912913914915916917918919\
    920921922923924925926927928929930931932933934935936937938939\
    940941942943944945946947948949950951952953954955956957958959\
    960961962963964965966967968969970971972973974975976977978979\
    980981982983984985986987988989990991992993994995996997998999";