#include <bits/stdc++.h>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int main(){
  int f[45];
  f[0]=f[1]=1;
  r(i,2,45)f[i]=f[i-1]+f[i-2];
  int a;cin>>a;
  cout<<f[a]<<endl;
}
### Prompt

Develop a solution in Cpp 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>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int main(){
  int f[45];
  f[0]=f[1]=1;
  r(i,2,45)f[i]=f[i-1]+f[i-2];
  int a;cin>>a;
  cout<<f[a]<<endl;
}
```