Hourglass Sum

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

namespace _16.Hourglass_Sum
{
    class Program
    {
        static void Main(string[] args)
        {
            long[][] matrix = new long[6][];

            for (int row = 0; row < matrix.Length; row++)
            {
                matrix[row] = Console.ReadLine().Split().Select(long.Parse).ToArray();
            }

            long maxSum = long.MinValue;

            for (int row = 0; row < matrix.Length - 2; row++)
            {
                for (int col = 0; col < matrix.Length - 2; col++)
                {
                    long sum = (long)matrix[row][col] + matrix[row][col + 1] + matrix[row][col + 2] +
                        matrix[row + 1][col + 1] +
                        matrix[row + 2][col] + matrix[row + 2][col + 1] + matrix[row + 2][col + 2];

                    if (sum > maxSum)
                    {
                        maxSum = sum;
                    }
                }
            }
            Console.WriteLine(maxSum);
        }
    }
}