static auto fast_io = []

{

	ios::sync_with_stdio(false);

	cout.tie(nullptr);

	cin.tie(nullptr);

	return 0;

}();

class Solution {

public:

    int climbStairs(int n)

    {

        int dp[n + 1];

        dp[0] = dp[1] = 1;      

        for (int i = 2; i <= n; ++i) dp[i] = dp[i - 1] + dp[i - 2];

        return dp[n];

    }

};