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