994. Rotting Oranges

You are given an m x n grid where each cell can have one of three values: - 0 representing an empty cell, - 1 representing a fresh orange, or - 2 representing a rotten orange. Every minute, any fresh orange that is 4-directionally adjacent to a rotten orange becomes rotten. Return the minimum number of minutes that must elapse until no cell has a fresh orange. If this is impossible, return -1