#include <iostream>
using namespace std;

int main(){
  int a[45];
  int n;
  a[0] = a[1] = 1;
  cin >> n;
  for (int i=2;i<=n;i++){
    a[i] = a[i-1] + a[i-2];
  }
  cout << a[n] << endl;
  return 0;
}


### Prompt

Construct a Cpp code solution to the problem outlined:

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 main(){
  int a[45];
  int n;
  a[0] = a[1] = 1;
  cin >> n;
  for (int i=2;i<=n;i++){
    a[i] = a[i-1] + a[i-2];
  }
  cout << a[n] << endl;
  return 0;
}


```