#include <iostream>

int main(){
  int n;
  std::cin >> n;
  int dp[n+1];
  dp[0]=1; dp[1]=1;
  for(int i=2;i<=n;i++) dp[i]=dp[i-1]+dp[i-2];
  std::cout << dp[n] << std::endl;
}
### Prompt

In CPP, your task is to solve 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 <iostream>

int main(){
  int n;
  std::cin >> n;
  int dp[n+1];
  dp[0]=1; dp[1]=1;
  for(int i=2;i<=n;i++) dp[i]=dp[i-1]+dp[i-2];
  std::cout << dp[n] << std::endl;
}
```