#include <iostream>

int Fib[45];

int main(){
  int n;
  std::cin >> n;
  Fib[0]=Fib[1]=1;

  for(int i=2; i<=n; i++){
    Fib[i] = Fib[i-1]+Fib[i-2];
  }
  std::cout << Fib[n] << std::endl;

  return 0;
}


### 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 <iostream>

int Fib[45];

int main(){
  int n;
  std::cin >> n;
  Fib[0]=Fib[1]=1;

  for(int i=2; i<=n; i++){
    Fib[i] = Fib[i-1]+Fib[i-2];
  }
  std::cout << Fib[n] << std::endl;

  return 0;
}


```