using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
static class Md4
{
    public static string Md4Hash(this string input)
    {
        // get padded uints from bytes
        List<byte> bytes = Encoding.ASCII.GetBytes(input).ToList();
        uint bitCount = (uint)(bytes.Count) * 8;
        bytes.Add(128);
        while (bytes.Count % 64 != 56) bytes.Add(0);
        var uints = new List<uint>();
        for (int i = 0; i + 3 < bytes.Count; i += 4)
            uints.Add(bytes[i] | (uint)bytes[i + 1] << 8 | (uint)bytes[i + 2] << 16 | (uint)bytes[i + 3] << 24);
        uints.Add(bitCount);
        uints.Add(0);

        // run rounds
        uint a = 0x67452301, b = 0xefcdab89, c = 0x98badcfe, d = 0x10325476;
        Func<uint, uint, uint> rol = (x, y) => x << (int)y | x >> 32 - (int)y;
        for (int q = 0; q + 15 < uints.Count; q += 16)
        {
            var chunk = uints.GetRange(q, 16);
            uint aa = a, bb = b, cc = c, dd = d;
            Action<Func<uint, uint, uint, uint>, uint[]> round = (f, y) =>
            {
                foreach (uint i in new[] { y[0], y[1], y[2], y[3] })
                {
                    a = rol(a + f(b, c, d) + chunk[(int)(i + y[4])] + y[12], y[8]);
                    d = rol(d + f(a, b, c) + chunk[(int)(i + y[5])] + y[12], y[9]);
                    c = rol(c + f(d, a, b) + chunk[(int)(i + y[6])] + y[12], y[10]);
                    b = rol(b + f(c, d, a) + chunk[(int)(i + y[7])] + y[12], y[11]);
                }
            };
            round((x, y, z) => (x & y) | (~x & z), new uint[] { 0, 4, 8, 12, 0, 1, 2, 3, 3, 7, 11, 19, 0 });
            round((x, y, z) => (x & y) | (x & z) | (y & z), new uint[] { 0, 1, 2, 3, 0, 4, 8, 12, 3, 5, 9, 13, 0x5a827999 });
            round((x, y, z) => x ^ y ^ z, new uint[] { 0, 2, 1, 3, 0, 8, 4, 12, 3, 9, 11, 15, 0x6ed9eba1 });
            a += aa; b += bb; c += cc; d += dd;
        }

        // return hex encoded string
        byte[] outBytes = new[] { a, b, c, d }.SelectMany(BitConverter.GetBytes).ToArray();
        return BitConverter.ToString(outBytes).Replace("-", "").ToLower();
    }
    static void Main() { Console.WriteLine("Rosetta Code".Md4Hash()); }
}