You are climbing a stair case. It takes *n* steps to reach to the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

**Note:** Given *n* will be a positive integer.

**Example 1:**

Input:2Output:2Explanation:There are two ways to climb to the top. 1. 1 step + 1 step 2. 2 steps

**Example 2:**

Input:3Output:3Explanation: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