#include <cstdio>
#include <iostream>
using namespace std;

int main(){
	long long f[50];
	f[0]=1;
	f[1]=1;
	
	for(int i=2; i<45; ++i) f[i]=f[i-1]+f[i-2];
	
	int n;
	scanf(" %d", &n);
	cout << f[n] << endl;
}
### Prompt

Your challenge is to write 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 <cstdio>
#include <iostream>
using namespace std;

int main(){
	long long f[50];
	f[0]=1;
	f[1]=1;
	
	for(int i=2; i<45; ++i) f[i]=f[i-1]+f[i-2];
	
	int n;
	scanf(" %d", &n);
	cout << f[n] << endl;
}
```