Помогите написать программу C#

 using System; 

namespace New_Project 

{ public static class Program 

{ public static void Main() 

{ int i, j, k, m, n; 

  Random rnd = new Random(); 

  Console.Write("n m: "); 

  var s = Console.ReadLine().Split(" "); 

  n = int.Parse(s[0]); m = int.Parse(s[1]); 

  int [,] A = new int [n, m]; 

  Console.WriteLine(); 

  for (i = 0; i < n; i++) 

{ for (j = 0; j < m; j++) 

{ A[i,j] = rnd.Next() % 199 - 99; 

  Console.Write("{0,4}", A[i,j]); } 

  Console.WriteLine(); } 

  Console.WriteLine(); 

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

{ k = A[3,j]; A[3,j] = A[4,j]; A[4,j] = k; } 

  for (i = 0; i < n; i++) 

{ for (j = 0; j < m; j++) 

  Console.Write("{0,4}", A[i,j]); 

  Console.WriteLine(); } } } } 

 using System; 

namespace moocher 

{ 

    class Program 

    { 

        public static void Main(string[] args) 

        {     

            var rand = new Random(); 

            int[,] a = new int[int.Parse(Console.ReadLine()), int.Parse(Console.ReadLine())]; 

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

            { 

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

                { 

                    a[i, j] = rand.Next(-50, 50); 

                    Console.Write("{0,4}", a[i, j]); 

                }                 

                Console.WriteLine(); 

            } 

            if (a.GetLength(0) >= 5) 

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

                    if (a[3, j] != a[4, j]) 

                    { 

                        a[3, j] ^= a[4, j]; 

                        a[4, j] ^= a[3, j]; 

                        a[3, j] ^= a[4, j]; 

                    } 

            Console.WriteLine(); 

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

            { 

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

                    Console.Write("{0,4}", a[i, j]); 

                Console.WriteLine(); 

            } 

            Console.ReadKey(); 

        } 

    } 

}