#include <bits/stdc++.h>
using namespace std;
long long dp[50];
long long fib(int n){
if (n<=1) return 1;
if (dp[n]) return dp[n];
return dp[n]=fib(n-1)+fib(n-2);
}
int main(){
int n; cin>>n; cout<<fib(n)<<endl;
}

### Prompt

Please provide a CPP coded solution to the problem described below:

Write a program which prints $n$-th fibonacci number for a given integer $n$. The $n$-th fibonacci number is defined by the following recursive formula:

\begin{equation*} fib(n)= \left \\{ \begin{array}{ll} 1 & (n = 0) \\\ 1 & (n = 1) \\\ fib(n - 1) + fib(n - 2) & \\\ \end{array} \right. \end{equation*}

Constraints

* $0 \leq n \leq 44$

Input

An integer $n$ is given.

Example

Input

3


Output

3

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
long long dp[50];
long long fib(int n){
if (n<=1) return 1;
if (dp[n]) return dp[n];
return dp[n]=fib(n-1)+fib(n-2);
}
int main(){
int n; cin>>n; cout<<fib(n)<<endl;
}

```