import java.util.TreeSet;
public class Main {
public static void main(String[] args) {
TreeSet tSet = new TreeSet();
System.out.println("Size of TreeSet : " + tSet.size());
tSet.add(new Integer("1"));
tSet.add(new Integer("2"));
tSet.add(new Integer("3"));
System.out.println(tSet.size());
// remove one element from TreeSet using remove method
tSet.remove(new Integer("1"));
System.out.println("Size of TreeSet after removal : " + tSet.size());
}
}