Climbing Stairs

You are climbing a staircase with n steps. Each time you can climb either 1 or 2 steps. Return the number of distinct ways to reach the top.

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Example 1

Input: n = 2
Output: 2
Explanation: Two ways to climb 2 steps: (1+1) or (2).

Example 2

Input: n = 3
Output: 3
Explanation: Three ways: (1+1+1), (1+2), or (2+1).

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Constraints

• 1 <= n <= 45