Given a m x n binary matrix mat. In one step, you can choose one cell and flip it and all the four neighbours of it if they exist (Flip is changing 1 to 0 and 0 to 1). A pair of cells are called neighboors if they share one edge. Return the minimum number of steps required to convert mat to a zero matrix or -1 if you cannot. Binary matrix is a matrix with all cells equal to 0 or 1 only. Zero matrix is a matrix with all cells equal to 0. Example 1: Input: mat = [[0,0],[0,1]] Output: 3 Explanation: One possible solution is to flip (1, 0) then (0, 1) and finally (1, 1) as shown. Example 2: Input: mat = [[0]] Output: 0 Explanation: Given matrix is a zero matrix. We don't need to change it. Example 3: Input: mat = [[1,1,1],[1,0,1],[0,0,0]] Output: 6 Example 4: Input: mat = [[1,0,0],[1,0,0]] Output: -1 Explanation: Given matrix can't be a zero matrix Constraints: m == mat.length n == mat[0].length 1 <= m <= 3 1 <= n <= 3 mat[i][j] is 0 or 1.