using System;           

public class Program

{

    //Give a 2D matrix of NxN elements, write a function to calculate sum of columns where first element is even number. Function returns value of sum.

​

​

    public static void Main()

    {

//int[][] arr = new int[6][];

        int sum =0;

            int[,] arr = new int[3,3]{ {0,1,3}, {3,2,3}, {5,1,7}};

         //  arr[arr_i] = Array.ConvertAll(arr_temp,Int32.Parse);

        int j=0;int i=0;

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

                {

                int mod = arr[0,j]%2;

                if(mod==0)

                {

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

                    sum+= arr[i,j];

                    }

                }       

            }

        Console.WriteLine(sum); 

    }

}

​