using System;

using System.Text;

public class Program

{

    const int BITCOUNT = 30;

    const int BITMASK = (1 << BITCOUNT/2) - 1;

    static uint roundFunction(uint number) {

      return (((number ^ 47894) + 25) << 1) & BITMASK;

    }

    static uint crypt(uint number) {

      uint left = number >> (BITCOUNT/2);

      uint right = number & BITMASK;

      for (int round = 0; round < 10; ++round) {

        left = left ^ roundFunction(right);

        uint temp = left; left = right; right = temp;

      }

      return left | (right << (BITCOUNT/2));

    }

    const string ALPHABET= "AG8FOLE2WVTCPY5ZH3NIUDBXSMQK7946";

    static string couponCode(uint number) {

      StringBuilder b = new StringBuilder();

      for (int i=0; i<6; ++i) {

        b.Append(ALPHABET[(int)number&((1 << 5)-1)]);

        number = number >> 5;

      }

      return b.ToString();

    }

    static uint codeFromCoupon(string coupon) {

      uint n = 0;

      for (int i = 0; i < 6; ++i)

        n = n | (((uint)ALPHABET.IndexOf(coupon[i])) << (5 * i));

      return n;

    }

    public static void Main()

    {

        Console.WriteLine(ALPHABET.Length.ToString());

        Console.WriteLine("Hello World");

        var test = codeFromCoupon("SAVESA");

        var couponTest = couponCode(crypt(1));

        Console.WriteLine(test.ToString());

        Console.WriteLine(couponTest);

    }

}