Single Number: Find the Unique Element

Given a non-empty list of integers in which every element appears exactly twice except for one unique element that appears only once, your task is to identify this unique element.

You can use the bitwise XOR operation to solve this problem efficiently. Recall that the XOR operation satisfies the properties $$a \oplus a = 0$$ and $$0 \oplus a = a$$, which makes it ideal for this task.

inputFormat

The input is read from standard input (stdin). The first line contains an integer \(n\) (which is odd), representing the total number of elements. The second line contains \(n\) space-separated integers. It is guaranteed that every integer appears exactly twice except for one integer that appears exactly once.

outputFormat

Print a single line to standard output (stdout) containing the unique element that appears only once.

1
5

5