import java.util.TreeSet;

/*
 * Example of pollFirst() method.
 */
public class TreeSetExample
{
    public static void main( String[] args )
    {

        TreeSet<Integer> treeSet = new TreeSet<Integer>();

        treeSet.add(40);
        treeSet.add(20);
        treeSet.add(30);
        treeSet.add(10);
        treeSet.add(50);

        System.out.println("treeSet : " + treeSet + "\n");

        /*
         * Retrieves and removes the first (lowest) element, or returns null if
         * this set is empty.
         */

        Integer value = treeSet.pollFirst();
        System.out.println("value : " + value);

        System.out.println("treeSet : " + treeSet + "\n");

    }
}