AT_abc473_b [ABC473B] Old Maid

Takahashi currently has $ N $ cards. The $ i $ -th $ (1\le i\le N) $ card has the integer $ A _ i $ written on it. He repeats the following operation as many times as possible. - Choose two different cards with the same integer written on them, and eat those two cards. The eaten cards are permanently removed and cannot be chosen in subsequent operations. Find the sum of the integers written on the cards that remain when the operation can no longer be performed.

The input is given from Standard Input in the following format: > $ N $ $ A _ 1 $ $ A _ 2 $ $ \cdots $ $ A _ N $

Output the sum of the integers written on the remaining cards.

### Sample Explanation 1 For example, Takahashi operates as follows. 1. The fourth card and sixth card both have $ 8 $ written on them, so he chooses them and eats them. 2. The first card and fifth card both have $ 2 $ written on them, so he chooses them and eats them. 3. The third card and seventh card both have $ 1 $ written on them, so he chooses them and eats them.  Thus, the sum of the integers written on the remaining cards is $ 7+8=15 $ . Note that there are three cards with $ 8 $ written on them, so once two of them are eaten, the remaining one cannot be eaten. ### Sample Explanation 2 It is possible that Takahashi cannot perform the operation even once. ### Constraints - $ 1\le N\le100 $ - $ 1\le A _ i\le100\ (1\le i\le N) $ - All input values are integers.