#include"iostream"
using namespace std;
int main()
{
  int a,b,c;
  int n;
  cin>>n;
  c=1;
  a=1;b=1;
  for(int i=1;i<n;i++)
    {
      c=a+b;
      a=b;
      b=c;
    }
  cout<<c<<endl;
  return 0;
}

### Prompt

Please provide a CPP coded solution 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"
using namespace std;
int main()
{
  int a,b,c;
  int n;
  cin>>n;
  c=1;
  a=1;b=1;
  for(int i=1;i<n;i++)
    {
      c=a+b;
      a=b;
      b=c;
    }
  cout<<c<<endl;
  return 0;
}

```