Problem Statement

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?

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Examples

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

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Constraints

• 1 ≤ n ≤ 45