#include <iostream>
using namespace std;

int main() {
  int n;
  long long x = 1;
  cin >> n;
  for (int i=2; i<=n; i++) {
    x *= i;
  }
  cout << x << endl;
}
### 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() {
  int n;
  long long x = 1;
  cin >> n;
  for (int i=2; i<=n; i++) {
    x *= i;
  }
  cout << x << endl;
}
```