1

#include <iostream>

using namespace std;

int main()
{
    int y;
    long long int fac;
    while(true)
    {
        fac=1;
        cin>>y;
    if(y<=0)
            break;
            for(int k=1; k<=y; k++)
            {
                fac*=k;

            }

            cout<<fac<<endl;

    }
    return 0;
}