import java.util.TreeSet;

public class TestTreeSet {

	public static void main(String[] args) {
		TreeSet<Item> set = new TreeSet<Item>();
		set.add(new Item(2));
		set.add(new Item(5));
		set.add(new Item(2));
		System.out.println(set);
	}

	static class Item {
		int n;
		Item(int n) {
			this.n = n;
		}
		public String toString() {
			return "Item " + n;
		}
	}
}