DNA

using System;

class ProgrammerDNA
{
    public static char[] letters = new char[7];

    static void Main()
    {
        int size = int.Parse(Console.ReadLine());
        char ch = char.Parse(Console.ReadLine());
        int asciiCode = Convert.ToInt32(ch);
        FillArrayOfChars(asciiCode);

        bool direction = true;
        int symbol = 0;
        int dot = 3;

        for(int row = 0,diamond = 0; row < size; row++,diamond++)
        {
            if(diamond != 0 && diamond % 7 == 0)
            {
               if (symbol == 7)
               {
                 symbol = 0;
               }
               Console.WriteLine("{0}{1}{0}", new string('.',3),letters[symbol]);
               symbol++;
               continue;
            }
            Console.Write("{0}", new string('.',dot));

            for(int col = 0;col < 7-dot*2; col++)
            {
               if (symbol == 7)
               {
                 symbol = 0;
               }
               Console.Write("{0}",letters[symbol]);
               symbol++;
            }
          Console.Write("{0}", new string('.',dot));
          Console.WriteLine();

          if(direction)
          {
            if(dot == 0)
            {
              direction = false;
              dot++;
              continue;
            }
            dot--;
          }
          if(!direction)
          {
            if(dot == 3)
            {
              direction = true;
              dot--;
              continue;
            }
            dot++;
          }
        }
    }
    private static void FillArrayOfChars(int charNum)
    {
        for (int i = 0; i < 7; i++)
        {
            if (charNum == 72)
            {
                charNum = 65;
            }
            letters[i] = (char)(charNum);
            charNum++;
        }
    }
}