#include <iostream>

using namespace std;

int Factorial(size_t n);

int main() {
    size_t i;

    for(i=0;i<=12; i++) {
        cout << i << "! = " << Factorial(i) << endl;
    }
}


int Factorial(size_t n) {
    if (n == 0 ) {
       return 1;
    } else {
       return n*Factorial(n-1);
    }
}