#include<iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
    int F[50];
    F[0]=F[1]=1;
    for(int i=2;i<=n;i++)
        F[i]=F[i-1]+F[i-2];
    cout<<F[n]<<"\n";
    return 0;
}


### Prompt

Create a solution in CPP for 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>
using namespace std;
int main(){
    int n;
    cin>>n;
    int F[50];
    F[0]=F[1]=1;
    for(int i=2;i<=n;i++)
        F[i]=F[i-1]+F[i-2];
    cout<<F[n]<<"\n";
    return 0;
}


```