Chef and Big Matrix

Chef has a rectangular table consisting of N rows and M columns. Rows are numbered by integers from 1 to N from top to bottom and columns are numbered from 1 to M from left to right. Let (x, y) denote the cell corresponding to xth row and yth column. Chef has two bunnies, both initially at the cell (1, 1). He wants them to get to the cell (N, M). Each of the bunny can move from some cell (x, y) t