/* package codechef; // don't place package name! */

import java.util.*;

import java.lang.*;

import java.io.*;

class DoublyLinkedList<Integer>

{

public static class Node<Integer>

{

private Integer element;

private Node<Integer> prev;

private Node<Integer> next;

public Node<Integer>(Integer e,Node<Integer> p,Node<Integer> n){

element = e;

prev = p;

next = e;

}

public Integer getElement(){

return element;

}

public Node<Integer> getPrevious(){

return prev;

}

public getNext(){

return next;

}

public setPrev(Node<Integer> p){

prev = p;

}

public setNext(Node<Integer> n){

next = n;

}

}

private Node<Integer> header ;

private Node<Integer> trailer;

private Integer size =0;

publc DoublyLinkedList(){

header = new Node<Integer>(0,null,null);

trailer = new Node<Integer>(0,null,null);

header.setNext(trailer);

}

public int size(){

return size;

}

public int isEmpty(){

return size==0;

}

public Integer getFirst(){

if(isEmpty()== true)

return -99999;

return header.getNext().getElement();

}

public Integer getLast(){

if(isEmpty()== true)

return -99999;

return trailer.getPrev().getElement();

}

public void addBetween(Integer ele,Node<Integer> previous,Node<Integer> next){

Node<Integer> newele = new Node<Integer>(ele,previous,next);

previous.setNext(newele);

next.setPrev(newele);

size++;

}

private void remove(Node<Integer> node)

{

Node<Integer> previous = node.getPrev();

Node<Integer> next = node.getNext();

size--;

previous.setNext(next);

next.setPrev(previous);

return node.getElement();

}

public void addFirst(Integer ele){

addBetween(ele,header,header.getNext());

}

public void addLast(Integer ele){

addBetween(ele,trailer,trailer.getPrev());

}

public static void main (String[] args) throws java.lang.Exception

{

}

}