Sum of Unique Elements

You are given an array of integers. Your task is to compute the sum of all unique elements in the array, where a unique element is defined as an element that appears exactly once.

In mathematical terms, if the array is \( A = [a_1, a_2, \dots, a_n] \), then you need to find:

[ S = \sum_{\substack{a \in A \ \text{frequency}(a)=1}} a ]

For example, consider the array [1, 2, 3, 2, 4, 1]. The number 3 and 4 appear exactly once, so the answer would be 3 + 4 = 7.

inputFormat

The first line of the input contains a single integer n, representing the number of elements in the array. The second line contains n space-separated integers.

outputFormat

Output a single integer — the sum of all unique elements in the array.## sample

6
1 2 3 2 4 1

7