The cost of adding two numbers equals to their sum. For example to add and costs . The cost of addition and is . We can add numbers in several ways:
(cost = ), (cost = ). Total =
(cost = ), (cost = ). Total =
(cost = ), (cost = ). Total =
We hope you understood the task. You must add all numbers so that the total cost of summation will be the smallest.
First line contains positive integer . Second line contains nonnegative integers, each no more than .
Print the minimum total cost of summation.