Given an `m x n` binary matrix `mat`, return the number of submatrices that have all ones.

Example 1:

    Input: mat = [[1,0,1],[1,1,0],[1,1,0]]
    Output: 13
    Explanation:
    There are 6 rectangles of side 1x1.
    There are 2 rectangles of side 1x2.
    There are 3 rectangles of side 2x1.
    There is 1 rectangle of side 2x2.
    There is 1 rectangle of side 3x1.
    Total number of rectangles = 6 + 2 + 3 + 1 + 1 = 13.

Example 2:

    Input: mat = [[0,1,1,0],[0,1,1,1],[1,1,1,0]]
    Output: 24
    Explanation:
    There are 8 rectangles of side 1x1.
    There are 5 rectangles of side 1x2.
    There are 2 rectangles of side 1x3.
    There are 4 rectangles of side 2x1.
    There are 2 rectangles of side 2x2.
    There are 2 rectangles of side 3x1.
    There is 1 rectangle of side 3x2.
    Total number of rectangles = 8 + 5 + 2 + 4 + 2 + 2 + 1 = 24.

Constraints:

- `1 <= m, n <= 150`
- `mat[i][j]` is either `0` or `1`.