SumMatrix3x3

using System;

class MatrixBiggerSum
{
    static void Main()
    {
        Console.WriteLine("Enter the length of the matrix rows: ");
        int n = int.Parse(Console.ReadLine());
        Console.WriteLine("Enter the length of the matrix columns: ");
        int m = int.Parse(Console.ReadLine());

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


        // Read the matrix
        Console.WriteLine("Now the values!");
        for (int row = 0; row < matrix.GetLength(0); row++)
        {
            for (int col = 0; col < matrix.GetLength(1); col++)
            {
                Console.Write("matrix[{0},{1}] = ", row, col);
                matrix[row, col] = int.Parse(Console.ReadLine());
            }
            Console.WriteLine();
        }

        // Find the maximal sum platform of size 3 x 3
        int count = 3; // For the sum loop count = count (3 x 3)
        int bestSum = int.MinValue;
        int bestRow = 0;
        int bestCol = 0;

        for (int row = 0; row < matrix.GetLength(0) - (count - 1); row++)
        {
            for (int col = 0; col < matrix.GetLength(1) - (count - 1); col++)
            {
                //Get the sum - Loop
                int sum = 0;
                for (int i = row; i < count + row; i++)
                {
                    for (int j = col; j < count + col; j++)
                    {
                        sum += matrix[i, j];
                    }
                }

                if (sum > bestSum)
                {
                    bestSum = sum;
                    bestRow = row;
                    bestCol = col;
                }
            }
        }

        // Print the result
        Console.WriteLine("The best platform is:");

        for (int i = bestRow; i < count + bestRow; i++)
        {
            for (int j = bestCol; j < count + bestCol; j++)
            {
                Console.Write("{0, -4}", matrix[i, j]);
            }
            Console.WriteLine();
        }

        Console.WriteLine("The maximal sum is: {0} ", bestSum);
    }
}