import java.util.*;

public class TreeExample {

    public static void main (String[] argv)
    {
        // Java's library has tree variant called TreeSet.
        // We'll make an instance to hold String's.
        TreeSet<String> unusualWords = new TreeSet<String> ();

        // Put some stuff in.
        unusualWords.add ("queueing");        // Six vowels in a row.
        unusualWords.add ("psychorhythms");   // Longest with one vowel.
        unusualWords.add ("verisimilitudes"); // Longest with alternating vowel/consonant.
        unusualWords.add ("frillless");       // Three letters in a row.
        unusualWords.add ("bookkeeper");      // Three double-letter's in a row.
        unusualWords.add ("cwm");             // Pronounced "koom" (type of crevasse).
        unusualWords.add ("feedback");        // Contains all letters 'a' to 'f'.

        // Print.
        System.out.println (unusualWords);
    }

}