static class JIndividuList { }

static class JconcJIndividu extends JIndividuList {
  public JIndividu head;
  public JIndividuList tail;
  public JconcJIndividu() { head = null; tail = null; }
  public JconcJIndividu(JIndividu h, JIndividuList ntail) {
    head = h;
    tail = ntail;
  }
  public boolean isEmpty() {
    return (head == null && tail == null);
  }
  public boolean equals(Object o) {
    if (o instanceof JconcJIndividu) {
      JconcJIndividu obj = (JconcJIndividu) o;
      if (this.isEmpty() && obj.isEmpty()) {
        return true;
      } else if (!this.isEmpty() && !obj.isEmpty()) {
        return 
          head.equals(obj.head) && tail.equals(obj.tail);
      }
    }
    return false;
  }
}
