public static void Main()
Console.WriteLine("\x48\x65\x6c\x6c\x6f\x20\x57\x6f\x72\x6c\x64\x21");
Console.WriteLine("\x0048\x0065\x006c\x006c\x006f\x0020\x0057\x006f\x0072\x006c\x0064\x0021");
Console.WriteLine("\u0048\u0065\u006c\u006c\u006f\u0020\u0057\u006f\u0072\u006c\u0064\u0021");
Console.WriteLine('\x48' + '\x65' + '\x6c' + '\x6c' + '\x6f' + '\x20' +
'\x57' + '\x6f' + '\x72' + '\x6c' + '\x64' + '\x21');