public class Solution {
    public int climbStairs(int n) {
        int[] dp = new int[n+1];

        if(n<3) return n;

        dp[0] = 0;
        dp[1] = 1;
        dp[2] = 2;

        for(int i=3;i<n+1;i++){
            dp[i] = dp[i-1] + dp[i-2];
        }

        return dp[n];
    }
}