class Appointment {
  Time starttime, endtime;
  String text;

  Appointment(Time starttime, Time endtime, String text) {
    this.starttime = starttime; 
    this.endtime = endtime; 
    this.text = text; 
  }

  void prolong(int min) 
  { endtime = endtime.plus(min); }

  public void postpone(int min) 
  { starttime.flyt(min); endtime.flyt(min); }
  
  public String toString() 
  { return "fra " + starttime + " til " + endtime + ": " + text; }
}