Unique Paths

Problem A robot on an m x n grid starts top-left and moves only right or down. Count the unique paths to the bottom-right.

Input / Output

• Input: ints m, n. Output: number of paths.

Constraints

• 1 <= m, n <= 100; answer fits in a signed 32-bit int per classic constraints.

Example

• m = 3, n = 7 → 28; m = 3, n = 2 → 3.