import java.util.*;
public class setimp
{
    public static void main(String[] args) {
        HashSet<Integer> set=new HashSet<>();
        set.add(6);
        set.add(2);
        set.add(3);
        set.add(4);
        for(Integer n:set)
        {
            System.out.print(n+" ");
        }
        System.out.println();
        System.out.println(set.contains(3));
        System.out.println(set.isEmpty());
        System.out.println(set.size());
        set.clear();
        System.out.println(set.isEmpty());
        System.out.println(set.size());
    }
}