Programmer DNA

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


class Program
{
    static void printDNA(char firstLetter)
    {

    }
    static void Main(string[] args)
    {
        int howManyLines = Int32.Parse(Console.ReadLine()); ;
        char firstLetter = char.Parse(Console.ReadLine());
        bool up = true, down = false;
        bool restart = false;
        char[] Tletters = {'o','A', 'B', 'C', 'D', 'E', 'F', 'G'};
        int index = Array.IndexOf(Tletters, firstLetter);
        int counter = 1;

        for (int i = 0; i < howManyLines; i++)
        {
            Console.Write("{0}", new string('.', (7 - counter) / 2));
            for (int j = 0; j < counter; j++)
            {

                string format = Tletters[index].ToString();
                Console.Write(format);
                ;
                index++;
                if (index > 7)
                {
                    index = index % 7;
                }
            }
            Console.Write("{0}", new string('.', (7 - counter) / 2));
            if (counter <= 5 && down == false)
            {
                up = true;
            }
            else if (counter == 7)
            {
                down = true;
            }
            Console.WriteLine();
            if (restart == true)
            {
                counter -= 2;
                restart = false;
            }
            if (counter < 7 && up && down == false)
            {
                counter += 2;

            }

            else if (down)
            {
                counter -= 2;
                if (counter == 1)
                {
                    down = false;
                    up = true;
                    restart = true;
                }
            }

        }
    }
}