interface Set<A> {
  boolean contains(A x);
  void include(A x);
}

class TreeSet<A> implements Set<A> {
  private (A, A) -> boolean less;
  Tree<A> elems = new EmptyTree();
  
  public TreeSet((A, A) -> boolean less) {
    this.less = less;
  }
  public boolean contains(A x) {
    return elems.contains(less, x);
  }
  public void include(A x) {
    elems = elems.insert(less, x);
  }
}

public class TestForDuplicates {
  
  static boolean stringLess(String x, String y) {
    return x.compareTo(y) < 0;
  }
  
  public static void main(String[] args) {
    Set<String> s = new TreeSet(stringLess);
    for (int i = 1; i < args.length; i++)
      s.include(args[i]);
    System.out.println(s.contains(args[0]));
  }
}

public class TestForDuplicatesAnonymous {

  public static void main(String[] args) {
    Set<String> s = 
      new TreeSet(
		  fun(String x, String y) -> boolean { 
 	              return x.compareTo(y) < 0; 
                  }
		  );
    for (int i = 1; i < args.length; i++)
      s.include(args[i]);
    System.out.println(s.contains(args[0]));
  }
}