https://www.hackerrank.com/challenges/30-2d-arrays
Objective
Today, we're building on our knowledge of Arrays by adding another dimension.
Task
Calculate the hourglass sum for every hourglass in A, then print the maximum hourglass sum.
Input Format
There are 6 lines of input, where each line contains 6 space-separated integers describing 2D Array A; every value in A will be in the inclusive range of -9 to 9.
Output Format
Print the largest (maximum) hourglass sum found in A.
Sample Input
1 1 1 0 0 0
0 1 0 0 0 0
1 1 1 0 0 0
0 0 2 4 4 0
0 0 0 2 0 0
0 0 1 2 4 0
Sample Output
19