extern void printInt(int val);
extern void printNewlines(int num);

int fac(int num) {
    int input = num;
    int output = 1;
    int i = 1;

    if (input == 0) {
        output = 1;
    } else {
        while (i <= input) {
            output = output * i;
            i = i + 1;
        }
    }
    return output;
}

export int main() {
    printInt(fac(3));  printNewlines(1);
    printInt(fac(5));  printNewlines(1);
    printInt(fac(10)); printNewlines(1);
    return 0;
}