You are given a two dimensional array containing an array of integers and an integer K as arguments. Return the largest sum found by adding together K x K groups of integers in the two dimensional array.

There will always be at least K number of arrays in the two dimensional array and at least K number of integers in each inner array.

Requirements

Example #1

solve([
  [100, 150, 0, 0, 350],
  [160, 100, 0, 0, 0],
  [0, 0, 0, 0, 0],
  [0, 0, 200, 250, 0],
  [0, 0, 300, 200, 0],
], 2)
> 950

1. Since K = 2, we want to find the largest sum of numbers in a 2x2 group.
2. The groups 100,150 and 160,100 would return only 510.
3. The groups 200,250 and 300,200 would return 950, which is our largest sum.