Given an `n x n` integer `matrix`, return the minimum sum of any **falling path**. A falling path starts at any cell in the first row and chooses the cell directly below or diagonally below-left/right at each step (column changes by at most 1).
Example 1
Input:matrix = [[2,1,3],[6,5,4],[7,8,9]]
Output:13
Explanation:1 -> 5 -> 7 gives 13.
Constraints
- n == matrix.length == matrix[i].length
- 1 <= n <= 100
- -100 <= matrix[i][j] <= 100