Multidimensional Array Homework - 2

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace _02.MaximalSum3x3
{
    class Program
    {
        static void Main(string[] args)
        {
            //create randomly size matrix
            Random randomNumb = new Random();
            int rowsNumberN = randomNumb.Next(3,15);
            int colsNumberK = randomNumb.Next(3, 15);
            int[,] matrix = new int[rowsNumberN, colsNumberK];

            //create randomly generated matrix with elements till 100;
            matrix = RandomMatrix(matrix,rowsNumberN,colsNumberK);

            //print Matrix
            Print(matrix);
            //check for maximum sum
            CheckMaxSum(matrix,rowsNumberN,colsNumberK);

        }

        private static int[,] RandomMatrix(int[,] matrix, int rowsNumberN, int colsNumberK)
        {
            Random randomNumb = new Random();
            for (int i = 0; i < rowsNumberN; i++)
            {
                for (int j = 0; j < colsNumberK; j++)
                {
                    matrix[i, j] = randomNumb.Next(100);
                }
            }
            return matrix;
        }



        private static void CheckMaxSum(int[,] matrix, int rowsNumberN, int colsNumberK)
        {
            int bestSum = int.MinValue;
            int totalSum;
            int bestCellRow = 0;
            int bestCellCol = 0;

            for (int rows = 0; rows < rowsNumberN - 3; rows++)
            {
                for (int cols = 0; cols < colsNumberK - 3; cols++)
                {
                    totalSum = SumMatrix(matrix, rows, cols);

                    if (totalSum >= bestSum)
                    {
                        bestSum = totalSum;
                        bestCellRow = rows;
                        bestCellCol = cols;
                    }
                }
            }

            Console.WriteLine("The maximum sum is: {0}", bestSum);
            PrintSmallMatrix(matrix, bestCellRow, bestCellCol);
        }

        private static void PrintSmallMatrix(int[,] matrix, int rows, int cols)
        {
            Console.WriteLine("The coordinate of the first cell is ({0},{1})", rows+1,cols+1);
            for (int i = 0; i < 3; i++)
            {
                for (int j = 0; j < 3; j++)
                {
                    Console.Write("{0,3}", matrix[rows + i, cols + j]);
                }
                Console.WriteLine();
            }
        }

        private static int SumMatrix(int[,] matrix, int rows, int cols)
        {
            int totalSum=0;
            for (int i = 0; i < 3; i++)
            {
                for (int j = 0; j < 3; j++)
                {
                    totalSum += matrix[rows + i, cols + j];
                }
            }

            return totalSum;
        }

        private static void Print(int[,] matrix)
        {
            int lengthRows = matrix.GetLength(0);
            int lengthCols = matrix.GetLength(1);

            for (int i = 0; i < lengthRows; i++)
            {
                for (int j = 0; j < lengthCols; j++)
                {
                    Console.Write("{0,3} ",matrix[i,j]);
                }
                Console.WriteLine();
            }

        }
    }
}