The result is the (n + 1)th Fibonacci Number, using the formula in wikipedia

```
public class Solution {
private static final double Phi = (1.0 + Math.sqrt(5)) / 2.0;
private static final double phi = (1.0 - Math.sqrt(5)) / 2.0;
private static final double sqrt5 = Math.sqrt(5);
public int climbStairs(int n) {
n = n + 1;
return (int) Math.round((Math.pow(Phi, n) - Math.pow(phi, n)) / sqrt5);
}
}
```