#include<iostream>
using namespace std;
int main() {
	int n;
	cin >> n;
	long long int ans = 1;
	for (int i = 1; i <= n; i++) {
		ans = ans * i;
	}
	cout << ans << endl;
}

### 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 ans = 1;
	for (int i = 1; i <= n; i++) {
		ans = ans * i;
	}
	cout << ans << endl;
}

```