class X
{
Y b = new Y();
        X()
  {
  System.out.print("X");
  }
}

class Y
{
        Y()
                {
  System.out.print("Y");
                }
}

public class Z extends X
{
        Y y = new Y();

        Z()
{
System.out.print("Z");
}

        public static void main(String[] args)
  {
                new Z();
        }
}