Given an array of integers, where all elements but one occur twice, find the unique element.

Example a = [1, 2, 3, 4, 3, 2, 1] The unique element is 4.

Function Description

Complete the lonelyinteger function in the editor below.

lonelyinteger has the following parameter(s):

• int a[n]: an array of integers

Returns

• int: the element that occurs only once Input Format

The first line contains a single integer, , the number of integers in the array. The second line contains n space-separated integers that describe the values in a.

Constraints

• 1 <= n < 100
• It is guaranteed that n is an odd number and that there is one unique element.
• 0 <= a[i] <= 100, where 0 <= i < n.