public abstract class FunList {

  public abstract Integer car();
  public abstract FunList cdr();
  public abstract Integer sum ();

}

public class Empty extends FunList {

  public Integer car() {
    throw new java.util.NoSuchElementException ("Empty has no element.");
  }

  public FunList cdr() {
    throw new java.util.NoSuchElementException ("Empty has no tail.");
  }

  /**
  * @returns Integer 0.
  * The sum over the empty set is 0!  This way, recursion will terminate naturally.
  */
   public Integer sum () {
      return new Integer (0);
   }
}

public class Cons extends FunList {

  private Integer _car;
  /** @SBGen Variable (,cdr,,64)   */
	private FunList _cdr;

  public Cons( Integer car, FunList cdr ) {
    _car = car;
    _cdr = cdr;
  }

  public Integer car() {
    return car;
  }

  public FunList cdr() {
    return cdr;
  }

  /**
  * @returns the Integer sum of the elements in this and its tail.
  */
  public Integer sum () {
    int dat = _car.intValue ();
    int tailSum = _cdr.sum ().intValue ();
      return new Integer (dat + tailSum);
  }
}