CSharp Solution

using System;

class Solution
{
    static void Main(String[] args)
    {
        int[][] arr = new int[6][];
        for (int i = 0; i < 6; i++)
        {
            var tmp = Console.ReadLine().Split(' ');
            arr[i] = Array.ConvertAll(tmp, int.Parse);
        }

        int max = -9 * 7;
        for (int i = 0; i < 6; i++)
        {
            for (int j = 0; j < 6; j++)
            {
                if (j + 2 < 6 && i + 2 < 6)
                {
                    int sum = arr[i][j] + arr[i][j + 1] + arr[i][j + 2] + arr[i + 1][j + 1] + arr[i + 2][j] + arr[i + 2][j + 1] + arr[i + 2][j + 2];
                    if (sum > max) max = sum;
                }
            }
        }

        Console.WriteLine(max);
    }
}