Unique Integer Finder

You are given an array of n integers where every integer appears exactly twice except for one unique integer that appears only once. Your task is to find and output this unique integer.

It is guaranteed that the input follows the condition: the array has an odd number of elements, and exactly one element appears once while all others appear exactly twice.

You can solve this problem efficiently using the bitwise XOR operator, since for any integer n, n \oplus n = 0 and n \oplus 0 = n. Hence, the unique number can be determined by XOR-ing all the numbers.

Note: All equations are given in \( \LaTeX \) format.

inputFormat

The first line contains an integer n representing the number of elements in the array.

The second line contains n space-separated integers.

outputFormat

Output the unique integer that appears only once in the array.

## sample

1
1

1

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