#include<iostream>
#include<string>
using namespace std;
int main(){
	long long n,h=1;
	cin>>n;
	for(int i=n;i>1;i--)
		h*=i;
	cout<<h<<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>
#include<string>
using namespace std;
int main(){
	long long n,h=1;
	cin>>n;
	for(int i=n;i>1;i--)
		h*=i;
	cout<<h<<endl;
	return 0;
}
```