#include <iostream>

int add(int a, int b) {
    if (a == 0) return b;
    int s = a + b;
    return s;
}

int factorial(int n) {
    int r = 1;
    for (int i = 1; i <= n; ++i) r *= i;
    return r;
}

void runner() {
    for (int i=0;i<10;i++) {
        std::cout << add(i, i) << "\n";
    }
}

int main() {
    runner();
    return 0;
}