using System;
using System.Runtime.InteropServices;

class DNA
{
    static void Main()
    {
        int dnaSize = 7;
        int lenht = int.Parse(Console.ReadLine());
        char startChar = char.Parse(Console.ReadLine());
        char[] DNA = {'A','B','C','D','E','F','G'};
        int i = 0;
        switch (startChar)
        {
            case 'A':
                i = 0; break;
            case 'B':
                i = 1; break;
            case 'C':
                i = 2; break;
            case 'D':
                i = 3; break;
            case 'E':
                i = 4; break;
            case 'F':
                i = 5; break;
            case 'G':
                i = 6; break;
        }
        string middle = Convert.ToString(DNA[i]);

        int outerDots = 3;
       int b = 0;
        int c = 0;
        int counter = 0;
        while (true)
        {
            if (counter <= 3)
            {

                if (b % 3 == 0)
                {
                    if (b == 12)
                    {
                        middle = "";
                        outerDots = 1;
                        break;
                    }

                    Console.WriteLine(new string('.', outerDots) + middle + new string('.', outerDots));
                    startChar++;
                    outerDots--;
                }
                else
                {
                    if (i == 7)
                    {
                        i = 0;
                    }
                    middle += "" + DNA[i];

                }

                b++;



                if (b ==12)
                {
                    break;
                }
                i++;
            }
            else
            {

            }



        }
    }
}