#include <iostream>
using namespace std;

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

Create a solution in CPP for 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 a = 1;
	 while(n){
    a*=n--;
  }
	cout << a << endl;
	return 0; 
}
```