Assignment $-1$: Find max square

Given a $nn$ sparse matrix represented as a set of $($row$,$ col, val$),$ find the $($i$,$ j$)$

that $M(i,j)$ is maximum. $M(i,j)$ is the sum of values of its eight neighbors including

itself as shown in the figure below.

The input and output data are given as below;

if there are more than one maximum values, then the result is the first element in

row$-$wise order.