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.

Input

The input is given in the following format:

n
command₁
command₂
...
command_n

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

Output

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

Constraints

• 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

7
insert 5
insert 2
insert 3
insert 1
delete 3
insert 6
delete 5

Sample Output 1

6 1 2

Sample Input 2

9
insert 5
insert 2
insert 3
insert 1
delete 3
insert 6
delete 5
deleteFirst
deleteLast

Sample Output 2

1

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