using System;

using System.Text;

public class Program

{

    public static int mod(int m, int e, int n)

    {

        int[] array = new int[100];

        int num = 0;

        do

        {

            array[num] = e % 2;

            num++;

            e /= 2;

        }

        while (e != 0);

        int num2 = 1;

        for (int i = num - 1; i >= 0; i--)

        {

            num2 = num2 * num2 % n;

            bool flag = array[i] == 1;

            if (flag)

            {

                num2 = num2 * m % n;

            }

        }

        return num2;

    }

    public static string Enc(string s, int e, int n)

    {

        int[] array = new int[s.Length];

        for (int i = 0; i < s.Length; i++)

        {

            array[i] = (int)s[i];

        }

        int[] array2 = new int[array.Length];

        for (int i = 0; i < array.Length; i++)

        {

            array2[i] = mod(array[i], e, n);

        }

        string text = "";

        for (int i = 0; i < array.Length; i++)

        {

            text += (char)array2[i];

        }

        return Convert.ToBase64String(Encoding.Unicode.GetBytes(text));

    }

    public static void Main()

    {

        Console.WriteLine(Enc("A", 0x23C5, 0xA09D));

    }

}