A community festival hands out numbered wristbands to attendees entering a raffle. Because the wristband printer occasionally double-prints a stack, a small number of codes end up issued to two different attendees, while every other code is issued to exactly one attendee. Under the raffle's tie-break rule, only attendees holding a code that was issued to exactly one person are eligible for the grand prize, and the prize pool is split according to the sum of those unique codes.

Given the list of wristband codes actually issued (in the order they were handed out), compute the sum of every code that appears in the list exactly once.

Input format

The first line contains a single integer n, the number of wristbands issued. The second line contains n space-separated integers a_1 ... a_n, the wristband codes.

Output format

Print a single integer: the sum of every code that occurs exactly once among a_1 ... a_n. If no code is unique, print 0.

Constraints

• 1 <= n <= 100
• 1 <= a_i <= 100

4
1 2 3 2

4

5
1 1 1 1 1

0