give m x n binary matrix mat return number submatrice one example 1input mat 101110110output 13explanation there 6 rectangle 1x1there 2 rectangle 1x2there 3 rectangle 2x1there 1 rectangle 2x2 there 1 rectangle 3x1total number rectangle 6 2 3 1 1 13example 2input mat 011001111110output 24explanation there 8 rectangle 1x1there 5 rectangle 1x2there 2 rectangle 1x3 there 4 rectangle 2x1there 2 rectangle 2x2 there 2 rectangle 3x1 there 1 rectangle 3x2 total number rectangle 8 5 2 4 2 2 1 24 Constraints1 m n 150matij 0 1