There is a robot on an `m x n` grid. The robot is initially located at the **top-left corner** (i.e., `grid[0][0]`). The robot tries to move to the **bottom-right corner** (i.e., `grid[m - 1][n - 1]`). The robot can only move either down or right at any point in time.
Given the two integers `m` and `n`, return *the number of possible unique paths that the robot can take to reach the bottom-right corner*.
The test cases are generated so that the answer will be less than or equal to `2 * 10^9`.
Examples
Example 1
Input:
m = 3, n = 7Output:
28Example 2
Input:
m = 3, n = 2Output:
3From the top-left corner, there are a total of 3 ways to reach the bottom-right corner:
1. Right -> Down -> Down
2. Down -> Down -> Right
3. Down -> Right -> Down
Constraints
- •
1 <= m, n <= 100
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