#include <iostream>
using namespace std;

int main() {
  int n;
  long long ans=1;
  cin >> n;
  for(int i=2; i<=n; i++) ans*=i;
  cout << ans <<endl;
  return 0;
}

### Prompt

Construct a Cpp code solution to the problem outlined:

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;
  long long ans=1;
  cin >> n;
  for(int i=2; i<=n; i++) ans*=i;
  cout << ans <<endl;
  return 0;
}

```