#include <iostream>

using namespace std;

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