#include<cstdio>
int main(){int n,i=1,f[45]={1,1};for(scanf("%d",&n);++i<=n;f[i]=f[i-1]+f[i-2]);printf("%d\n",f[n]);}
### 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<cstdio>
int main(){int n,i=1,f[45]={1,1};for(scanf("%d",&n);++i<=n;f[i]=f[i-1]+f[i-2]);printf("%d\n",f[n]);}
```