#include <iostream>
using namespace std;

int factorial(int n) {
    int pro = 1;
    if (n >= 0 and n <= 12) {
    for (int i = n; i > 0; --i) pro *= i;
    return pro;
    }
}
int main() {
    int n;
    cin >> n;
    cout << factorial(n) << endl;
}