Given an `n x n` array of integers `matrix`, return the minimum sum of any falling path through `matrix`.

A falling path starts at any element in the first row and chooses the element in the next row that is either directly below or diagonally left/right. Specifically, the next element from position `(row, col)` will be `(row + 1, col - 1)`, `(row + 1, col)`, or `(row + 1, col + 1)`.

Example 1:

    Input: matrix = [[2,1,3],[6,5,4],[7,8,9]]
    Output: 13
    Explanation: There are two falling paths with a minimum sum as shown.

Example 2:

    Input: matrix = [[-19,57],[-40,-5]]
    Output: -59
    Explanation: The falling path with a minimum sum is shown.

Constraints:

- `n == matrix.length == matrix[i].length`
- `1 <= n <= 100`
- `-100 <= matrix[i][j] <= 100`