class Program {
    public static void main(String[] args) {
        Person p = new Person("Roger", "Federer", 1985);
        Person q = new Person("Barack", "Obama", 1961);
        System.out.println(q.isAdult(2016));

        Person.isUpperCase = true;
        System.out.println(p);
        System.out.println(q);  // System.out.println(q.toString());

        Car c = new Car("ABC-123", 3, q);
        System.out.println(c.isValid());
        System.out.println(c);
    }
}