using System;

public class Program

{

    public static void Main()

    {

        char[] str = new char[10] {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J'};

        for (int i = 0; i <= 4; i++)

        {

            Console.Write(str[i]);

            Console.WriteLine(str[i + 5]);

        }

    }

}