//NoorBaizura bt Mohd Zin
// 1111168

#include <iostream>

using namespace std;

int main()
{
    long long x;
    int count=1;
    
    cin >> x;
    
    for (int i=1; i<=x; i++)
        count *= i;
        
    cout << count;
    
//    system ("pause");
    return 0;
    
}