you are given a matrix consisting of N rows and M columns. Each cell of the matrix contains one digit$(0,-9).$ Cells are adjacent if they share a common edge. it's possible to move from one cell to another directly only if they are adjacent.

find the largest group of cells such that:

$1.$ you can get from any cell in the group to any other by moving only through cells belong to the group.

$2.$ the difference between the largest and the smallest values of the cells in the group is at most $1.$

write a function:

def solution$($A$)$