#include <cstdio>

int main()
{
	int f[50]= {1, 1, 2};
	int n;
	scanf("%d", &n) ;
	for (int i = 3; i <= n; ++i)
		f[i] = f[i-1] + f[i-2];
	printf("%d\n", f[n]);
	
	return 0;
}

### Prompt

Your task is to create a Cpp solution to 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 <cstdio>

int main()
{
	int f[50]= {1, 1, 2};
	int n;
	scanf("%d", &n) ;
	for (int i = 3; i <= n; ++i)
		f[i] = f[i-1] + f[i-2];
	printf("%d\n", f[n]);
	
	return 0;
}

```