Java tutorial
import java.util.TreeSet; public class Main { public static void main(String[] args) { TreeSet<Integer> treeadd = new TreeSet<Integer>(); treeadd.add(1); treeadd.add(13); treeadd.add(17); treeadd.add(2); System.out.println("Size of the tree set is: " + treeadd.size()); } }