#include <stdio.h>
int main(){
int a[50],n;
a[0]=a[1]=1;
scanf("%d",&n);
for(int i=2;i<=n;i++)
a[i]=a[i-1]+a[i-2];
printf("%d\n",a[n]);
}
### 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 <stdio.h>
int main(){
int a[50],n;
a[0]=a[1]=1;
scanf("%d",&n);
for(int i=2;i<=n;i++)
a[i]=a[i-1]+a[i-2];
printf("%d\n",a[n]);
}
```