interface A {
  public abstract void a();
}

abstract class B implements A {}

abstract class C extends B {}

class D extends C {
  public void a() {
    System.out.println("D.a()");
  }
}

public class ResolverTestCase {
  public static void main(String args[]) {
    D d = new D();
    d.a();
    C c = new D();
    c.a();
  }
}