#include<iostream>
using namespace std;

int A[51];

void func(int n){
  if(n==50) return;
  A[n]=A[n-1]+A[n-2];
  func(n+1);
}

int main(){
  int n;
  cin >> n;
  A[0]=1; A[1]=1;
  func(2);

  cout << A[n] << endl;
}
### Prompt

Generate a cpp solution to the following problem:

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<iostream>
using namespace std;

int A[51];

void func(int n){
  if(n==50) return;
  A[n]=A[n-1]+A[n-2];
  func(n+1);
}

int main(){
  int n;
  cin >> n;
  A[0]=1; A[1]=1;
  func(2);

  cout << A[n] << endl;
}
```