Find the Unique Integer

You are given t test cases. In each test case, you are provided with an integer n followed by n integers. It is guaranteed that every integer in the test case appears exactly twice except for one integer which appears only once.

Your task is to find and output that unique integer from each test case.

You can use the XOR property $$a \oplus a = 0$$ and $$a \oplus 0 = a$$ to solve the problem in linear time.

inputFormat

The input is read from standard input and has the following format:

T
n_1
a_1 a_2 ... a_{n_1}
...
n_T
a_1 a_2 ... a_{n_T}

Where T is the number of test cases, and for each test case, n is the number of integers followed by n space-separated integers.

outputFormat

For each test case, output the unique integer that appears only once. The answers for the test cases should be printed in a single line separated by a space.

The output is written to standard output.

## sample

1
7
4 5 4 3 5 2 3

2

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