Climbing Stairs

You are climbing a staircase. It takes `n` steps to reach the top. Each time you can either climb `1` or `2` steps. In how many distinct ways can you climb to the top? **Example 1:** ``` Input: n = 2 Output: 2 Explanation: There are two ways to climb to the top. 1. 1 step + 1 step 2. 2 steps ``` **Example 2:** ``` Input: n = 3 Output: 3 Explanation: There are three ways to climb to the top. 1. 1 step + 1 step + 1 step 2. 1 step + 2 steps 3. 2 steps + 1 step ``` **Example 3:** ``` Input: n = 1 Output: 1 ```