#include<bits/stdc++.h>
using namespace std;
int main(){
  long long n,k=1;
  cin >> n;
  for(int i = 2;i <= n;i++) k*=i;
  cout << k << endl;
  return 0;
}
### 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<bits/stdc++.h>
using namespace std;
int main(){
  long long n,k=1;
  cin >> n;
  for(int i = 2;i <= n;i++) k*=i;
  cout << k << endl;
  return 0;
}
```