// Featherweight Java examples

class A extends Object {
    Integer x; 
    A(Integer x) { super(); this.x = x; }
    A incr() { return new A(this.x+1); }
}

class B extends A {
    Integer y;
    B(Integer x, Integer y) { super(x); this.y = y; }
    A incr() { return new B(this.x+1, this.y+1); }
}

class Feath1 {
    public static void main(String[] args) {
	B b = (B) (new B(3,4)).incr();
	System.out.println(b.x + " " + b.y);
    }
}