interface Comparator {
  public int compare(Object x, Object y);
}

class ByteComparator implements Comparator {
  public int compare(Object x, Object y){
    return ((Byte)x).byteValue() - ((Byte)y).byteValue();
  }
}

class Collections {
  public static Object max(Collection xs, Comparator c){
    Iterator xi = xs.iterator();
    Object w = xi.next();
    while(xi.hasNext()){
      Object x = xi.next();
      if(c.compare(w,x) < 0) w = x;
    }
    return w;
  }
}