using System;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("1 2 3");

        Console.WriteLine("4 5 6");

        Console.WriteLine("7 8 9");

        string[,  ] grid = {{"-", "-", "-"}, {"-", "-", "-"}, {"-", "-", "-"}};

        int num1 = 0;

        int num2 = 0;

        num1 = gridInput();

        num2 = gridInput();

        grid[num1, num2] = "X";

        for (int i = 0; i < 3; i++)

        {

            for (int j = 0; j < 3; j++)

            {

                Console.Write(grid[i, j]);

            }

​

            Console.WriteLine();

        }

    }

​

    public static int gridInput()

    {

        string input;

        int num;

        bool canConvert = false;

        do

        {

            input = Console.ReadLine();

            canConvert = int.TryParse(input, out num);

        }

        while (canConvert == false);

        return num;

    }

}