fn print(msg: string) #[builtin(Print)] {}
fn println(msg: string) { print(msg + "\n") }

fn mul(left: int, right: int) -> int {
    if left == 0 or right == 0 {
        0
    } else {
        left * right
    }
}

fn main() {
    if mul(10,2) == 20 {
        print("test 1 passed")
    }
    if mul(3,2) == 6 {
        print("test 2 passed")
    }
}