Time Limit : sec, Memory Limit : KB
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Doubly Linked List

Your task is to implement a double linked list.

Write a program which performs the following operations:

  • insert x: insert an element with key x into the front of the list.
  • delete x: delete the first element which has the key of x from the list. If there is not such element, you need not do anything.
  • deleteFirst: delete the first element from the list.
  • deleteLast: delete the last element from the list.


The input is given in the following format:


In the first line, the number of operations n is given. In the following n lines, the above mentioned operations are given in the following format:

  • insert x
  • delete x
  • deleteFirst
  • deleteLast


Print all the element (key) in the list after the given operations. Two consequtive keys should be separated by a single space.


  • The number of operations ≤ 2,000,000
  • The number of delete operations ≤ 20
  • 0 ≤ value of a key ≤ 109
  • The number of elements in the list does not exceed 106
  • For a delete, deleteFirst or deleteLast operation, there is at least one element in the list.

Sample Input 1

insert 5
insert 2
insert 3
insert 1
delete 3
insert 6
delete 5

Sample Output 1

6 1 2

Sample Input 2

insert 5
insert 2
insert 3
insert 1
delete 3
insert 6
delete 5

Sample Output 2