interface Comparator<A> {
  public int compare(A x, A y);
}

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

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