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# 62. Unique Paths

## Description

A robot is located at the top-left corner of a *m* x *n* grid (marked 'Start' in the diagram below).

The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in the diagram below).

How many possible unique paths are there?

Above is a 7 x 3 grid. How many possible unique paths are there?

**Example 1:**

Input:m = 3, n = 2Output:3Explanation:From the top-left corner, there are a total of 3 ways to reach the bottom-right corner: 1. Right -> Right -> Down 2. Right -> Down -> Right 3. Down -> Right -> Right

**Example 2:**

Input:m = 7, n = 3Output:28

**Constraints:**

`1 <= m, n <= 100`

- It's guaranteed that the answer will be less than or equal to
`2 * 10 ^ 9`

.