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

class B extends A {
  boolean b;
  void m() { 
    Library.print("B fields: ");
    Library.printi(a);
    Library.print(", ");
    Library.printb(b);
    Library.println("");
  }
}

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();
    ob.m();
  }
}