Unique Element Finder

You are given a list of integers in which exactly one integer appears only once, while every other integer appears exactly twice. Your task is to identify and output the unique integer.

This problem can be solved efficiently using the bitwise XOR operation. Recall that for any integer \(a\), we have \(a \oplus a = 0\) and \(a \oplus 0 = a\). Thus, XOR-ing all numbers in the list will cancel out those that appear twice, leaving the unique number.

Example:

Input: 4 3 2 4 1 3 2
Output: 1

inputFormat

The input is provided via standard input. It consists of a single line containing space-separated integers. The first line does not specify the number of integers; you must read all the integers from the input.

outputFormat

Output a single integer, which is the unique number that appears exactly once in the input.

## sample

1

1

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