#include<stdio.h>

int main()
{
	int fib1{ 1 }, fib2{ 1 }, n;

	scanf("%d", &n);
	for (int i = 1; i < n; ++i)
	{
		int tmp = fib2;
		fib2 += fib1;
		fib1 = tmp;
	}
	printf("%d\n", fib2);
	return 0;
}

### Prompt

Develop a solution in cpp 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<stdio.h>

int main()
{
	int fib1{ 1 }, fib2{ 1 }, n;

	scanf("%d", &n);
	for (int i = 1; i < n; ++i)
	{
		int tmp = fib2;
		fib2 += fib1;
		fib1 = tmp;
	}
	printf("%d\n", fib2);
	return 0;
}

```