Advanced Topics 7. Matrix of Palindromes

// Write a program to generate the following matrix of palindromes of 3 letters with r rows and c columns.

namespace _07.MatrixOfPalindromes
{
    using System;

    public class MatrixOfPalindromes
    {
        public static void Main(string[] args)
        {
            checked
            {
                int countR;
                do
                {
                    Console.Write("Enter Count of rows R: ");
                }
                while (!int.TryParse(Console.ReadLine(), out countR) || countR < 1);

                int countC;
                do
                {
                    Console.Write("Enter Count of columns C: ");
                }
                while (!int.TryParse(Console.ReadLine(), out countC) || countC < 1);

                char[] alphabet = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z' };

                Console.WriteLine("The Matrix of Palindromes is:\n");
                for (int rows = 0; rows < countR; rows++)
                {
                    for (int cols = rows; cols < rows + countC; cols++)
                    {
                        string palindrome = alphabet[rows % alphabet.Length].ToString() + alphabet[cols % alphabet.Length].ToString() + alphabet[rows % alphabet.Length].ToString();
                        Console.Write("{0,4}", palindrome);
                    }

                    Console.WriteLine();
                }

                Console.WriteLine();
            }
        }
    }
}