class Overriding {
    public static void main(String[] args) {
        System.out.println(new A().init());
    }
}

class A {
    public int init() {
        return 0;
    }

    public B x(A a) {
        return new B();
    }
}

class B extends A {
    public A x(A a) {
        return new A();
    }
}