Problem:
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Priority Queue

A priority queue is a data structure which maintains a set $S$ of elements, each of with an associated value (key), and supports the following operations:

$insert(S, k)$: insert an element $k$ into the set $S$

$extractMax(S)$: remove and return the element of $S$ with the largest key

Write a program which performs the $insert(S, k)$ and $extractMax(S)$ operations to a priority queue $S$.
The priority queue manages a set of integers, which are also keys for the priority.

Input

Multiple operations to the priority queue $S$ are given. Each operation is given by "insert $k$", "extract" or "end" in a line. Here, $k$ represents an integer element to be inserted to the priority queue.

The input ends with "end" operation.

Output

For each "extract" operation, print the element extracted from the priority queue $S$ in a line.

Constraints

The number of operations $\leq 2,000,000$

$0 \leq k \leq 2,000,000,000$

Sample Input 1

insert 8
insert 2
extract
insert 10
extract
insert 11
extract
extract
end

Sample Output 1

8
10
11
2

Solution in JAVA (judge verdict: Runtime Error)

import java.io.*;
import java.util.*;

public class Main {
	static public void main(String [] args) throws IOException{
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		PriorityQueue<Integer> que = new PriorityQueue<Integer>(10,new Comp());
		while (true){
			StringTokenizer st=new StringTokenizer(br.readLine());
			String str=st.nextToken();
			if (str.equals("insert")){
				que.add(Integer.parseInt(st.nextToken()));
			}else if (str.equals("extract")){
				System.out.println(que.poll());
			}else if (str.equals("end")) System.exit(1);
		}
	}
	private static class Comp implements Comparator<Integer>{
        public int compare(Integer x,Integer y){
            return (x < y) ? 1 : ((x == y) ? 0 : -1);
        }
    }
		
}