class A {
  int a;
  void m() { 
    Library.println("A fields: " +
		    Library.itos(a));
  }
}

class B extends A {
  boolean b;
  void m() { 
    Library.println("B fields: " +
		    Library.itos(a) + ", " +
		    Library.btos(b));
  }
}

class C {
  void main(string[] args) {
    A oa = new A();
    B ob = new B();

    if (args.length != 0) 
      oa = ob;

    oa.a = 412;
    ob.a = 413;
    ob.b = true;

    oa.m();
  }
}