using System;

using System.Runtime.InteropServices;

public static class Program

{

    public static void Main()

    {

        var guid = Guid.NewGuid();

        Console.WriteLine(guid.ToLong());

    }

        private static GuidConverter _converter;

​

        [StructLayout(LayoutKind.Explicit)]

        private struct GuidConverter

        {

            [FieldOffset(0)]

            public decimal Decimal;

            [FieldOffset(0)]

            public Guid Guid;

            [FieldOffset(0)]

            public long Long1;

            [FieldOffset(8)]

            public long Long2;

            [FieldOffset(0)]

            public ulong ULong1;

            [FieldOffset(8)]

            public ulong ULong2;

            [FieldOffset(0)]

            public int Int1;

            [FieldOffset(4)]

            public int Int2;

            [FieldOffset(8)]

            public int Int3;

            [FieldOffset(12)]

            public int Int4;

            [FieldOffset(0)]

            public uint UInt1;

            [FieldOffset(4)]

            public uint UInt2;

            [FieldOffset(8)]

            public uint UInt3;

            [FieldOffset(12)]

            public uint UInt4;

        }

        public static long ToLong(this Guid guid)

        {

            _converter.Guid = guid;

​

            return _converter.Long1;

        }

}