#include <iostream>
using namespace std;
int main() {
int n;
long int f = 1;
cin >> n;
for (int i = 2; i <= n; i++) {
f *= i;
}
cout << f;
return 0;
#include <iostream>
using namespace std;
int main() {
int n;
long int f = 1;
cin >> n;
for (int i = 2; i <= n; i++) {
f *= i;
}
cout << f;
return 0;
}