class A {
    private int a;
    public A(int a) { this.a = a; }

    @Override
    public boolean equals(Object o) {
        if(o instanceof A) {
            return this.a == ((A) o).a;
        }
        else {
            return false;
        }
    }
}

class B extends A {
    private int b;

    public B(int a, int b) { super(a); this.b = b; }

    @Override
    public boolean equals(Object o) {
        if(o instanceof B) {
            return this.equals(o) && this.b == ((B) o).b;
        }
        else {
            return false;
        }
    }
}