#include<bits/stdc++.h> 
using namespace std; 
long long n,f[49],x=1;
int main()
{
    cin>>n;
    f[0]=1;
    f[1]=1;
    for(int i=2;i<=n;i++)
        f[i]=(f[i-1]+f[i-2]);
    
    cout<<f[n]<<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<bits/stdc++.h> 
using namespace std; 
long long n,f[49],x=1;
int main()
{
    cin>>n;
    f[0]=1;
    f[1]=1;
    for(int i=2;i<=n;i++)
        f[i]=(f[i-1]+f[i-2]);
    
    cout<<f[n]<<endl;
}

```