Unique Paths in a 2D Matrix with Moves

Given a m x n 2D matrix, calculate the number of unique paths from the bottom-left corner to the top-right corner. You can only move up, right, or diagonally up-right at each step. Implement the function unique_paths(m: int, n: int) -> int and return the number of possible paths. Assume m and n are in the range [1, 100]. Provide test cases. Example Input 3 3