#include <bits/stdc++.h>

using namespace std;

int main()
{
    int n;
    cin >> n;
    vector<int>v(n+1);
    v[0] = 1, v[1] = 1;
    for(int i = 2; i <= n; i++) v[i] = v[i-1] + v[i-2];
    cout << v[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;

int main()
{
    int n;
    cin >> n;
    vector<int>v(n+1);
    v[0] = 1, v[1] = 1;
    for(int i = 2; i <= n; i++) v[i] = v[i-1] + v[i-2];
    cout << v[n] << endl;
}

```