#include <iostream>
using namespace std;

int main() {
	int n;
	cin >> n;
	long long int fact = 1;
	while (n > 0) {
		fact *= n;
		n--;
	}
	cout << fact << endl;
	return 0;
}
### Prompt

Your task is to create a CPP solution 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() {
	int n;
	cin >> n;
	long long int fact = 1;
	while (n > 0) {
		fact *= n;
		n--;
	}
	cout << fact << endl;
	return 0;
}
```