class X {
    Y b = new Y();
    X() {
        System.out.print("X");
    }
}
class Y {
    Y() {
        System.out.print("Y");
    }
}

public class UserDao extends X{
        Y y = new Y();
        UserDao(){
            System.out.print("Z");
        }
        public static void main(String[] args) {
            new UserDao();
        }
}