Competitions

# LinkedList Simulate Sum of Odd Elements

An empty Linked List is given initially. Simulate the next operations:

• push front x: add element x to the front of a Linked List;
• push back x: add element x to the back of a Linked List;
• pop front: remove element from the front of a Linked List;
• pop back: remove element from the back of a Linked List;

Let L = (a1, a2, ...., an) be the resulting Linked List. Find the sum of all its odd elements.

#### Input

Each line contains one of the operations described above. It is known that x is a nonnegative integer, no more than 1000. Final Linked List (after simulation) contains no more than 1000 elements.

#### Output

Print the sum of all odd elements of the resulting Linked List.

#### Example

After simulation the list will have the next form:

The sum of odd elements is 5 + 1 = 6.

Time limit 1 second
Memory limit 128 MiB
Input example #1
push back 7
push back 5
pop front
push front 2
push back 1

Output example #1
6

Author Michael Medvediev