using System;

public class Program

{

    public static void Main()

    {

        int[,] matrix = 

        {

            {1, 2, 3},

            {4, 5, 6},

            {7, 8, 9}

        };

        var left = 0;

        for(int i=0; i<matrix.GetLength(0); i++)

        {

            for(int j=0; j<matrix.GetLength(1); j++)

            {

                if (i == j)

                {

                    left = left + matrix[i, j];

                    Console.WriteLine(matrix[i, j]);

                }

            }

        }

        var right = 0;

        for(int i=0; i<matrix.GetLength(0); i++)

        {

            for(int j=0; j<matrix.GetLength(1); j++)

            {

                if (i == (matrix.GetLength(0) - 1- j))

                {

                    right = right + matrix[i, j];

                    Console.WriteLine(matrix[i, j]);

                }

            }

        }

        Console.WriteLine("--------------------");

        Console.WriteLine("Diagonal differenece");

        Console.WriteLine(left-right);

    }

}