The promotional season is over. The administration is happy with the results. And, they want to continue the campaign with a small change. As in previous Buy3 Pay2 campaign, the clients are free to choose any consecutive 3 items in the given order. Then, the cheapest of the group (3 items) will be free. However, this time clients cannot change the order of items. The purpose is to maximize the discount.

Question: Write a program that takes price of n items, then maximizes the profit for the client.

Input specification
You will be given an integer in the beginning: the number of items (n). In the following line, you will be given n integers, prices of n items where 0 ≤ n ≤ 30

Output specification:
Show one integer: max discount that the client can get.

Explanation:
For sample 1: Without changing the order of items, the client can choose (10 + 20 + 17) (16 + 19 + 16) and have $26 discount.
For sample 2: The client can choose (20 + 18 + 16) (15 + 16 + 12) and have $28 discount.