MatrixMaxSum

using System;
using System.Linq;

namespace MatrixMaxSum
{
    class Program
    {
        static void Main(string[] args)
        {
            int size = int.Parse(Console.ReadLine());
            int[,] matrix = FillMatrix(size);

            int[] coordinates = Console.ReadLine().
                Split().
                Select(int.Parse).
                ToArray();

            int maxSum = int.MinValue;
            int currSum = 0;
            int counter = 0;

            for (int i = 0; i < coordinates.Length; i += 2)
            {
                int[] currCoordinates = coordinates.Skip(i)
                    .Take(2)
                    .ToArray();
                int currRow = currCoordinates[0];
                int currCol = currCoordinates[1];

                while (currRow > 0)
                {
                    for (int j = currRow; j <= currRow; j++)
                    {
                        for (int k = 0; k <= currCol; k++)
                        {
                            currSum += matrix[j,k];
                        }
                    }
                    currRow--;
                }
            }
        }
        public static int[,] FillMatrix(int size)
        {
            int[,] matrix = new int[size, size];

            for (int row = 0; row < size; row++)
            {
                int[] currLine = Console.ReadLine()
                    .Split()
                    .Select(int.Parse)
                    .ToArray();

                for (int col = 0; col < size; col++)
                {
                    matrix[row, col] = currLine[col];
                }
            }
            return matrix;
        }
    }
}