import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.PriorityQueue;

public class MyClass
{
public static void main(String args[])
{
PriorityQueue<Integer> q = new PriorityQueue<Integer>();
q.add(1);
q.add(2);
q.add(3);
System.out.println(q.poll());
System.out.println(q.offer(4));
q.add(1);
q.remove(2);
System.out.println(q.peek());
System.out.println(q);
}
}