class A extends Object {
    public int x;
    private C y = new C();
    public A (C u) {
        x = this.y.x + 2;
        y = u;
    }
    public int add(int u) {
        this.x = 2*this.x+u;
    }
}

class B extends A {
    public int x = 0;
    public B (C u) {
        super(u);
    }
    public B () {
        this.x = 10;
    }
    public int add(int u) {
        this.x = u;
    }
}

class C extends Object {
    public int x = 7;
    C () {}
}

A z = new B(new C())
int w = z.x