#include <iostream>

using namespace std;

template <unsigned long long N>
unsigned long long factorial()
{
    return N * factorial<N-1>();
}

template <>
unsigned long long factorial<0>()
{
    return 1;
}

int main()
{
    cout << factorial<0>() << endl;
    cout << factorial<1>() << endl;
    cout << factorial<5>() << endl;
    cout << factorial<20>() << endl;
}