#include<iostream>
using namespace std;

int main()
{
	long long int x;
	cin >> x;
	
	for (int i = x-1; i > 0; --i){
		x *= i;
	}

	cout << x << endl;

	return 0;
}
### Prompt

Please create a solution in cpp to the following problem:

Write a program which reads an integer n and prints the factorial of n. You can assume that n ≤ 20.



Input

An integer n (1 ≤ n ≤ 20) in a line.

Output

Print the factorial of n in a line.

Example

Input

5


Output

120

### Response

```cpp
#include<iostream>
using namespace std;

int main()
{
	long long int x;
	cin >> x;
	
	for (int i = x-1; i > 0; --i){
		x *= i;
	}

	cout << x << endl;

	return 0;
}
```