Unique Numbers in Series

You are given T series of numbers. For each series, you need to determine its unique numbers. A unique number is defined as a number that appears exactly once in the series. The order of output must follow the order in which the numbers were first encountered.

If a series does not contain any unique number, print None as the result for that series.

Mathematically, a number x is unique in a series S if and only if $$count(x)=1$$, where $$count(x)$$ is the number of times x appears in S.

Example:

Input:
3
7
4 5 6 5 4 7 8
5
1 2 2 3 4
6
1 2 3 1 2 3
Output:
6 7 8
1 3 4
None

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inputFormat

The input is given via standard input (stdin) and follows the format below:

• The first line contains an integer T, the number of series.
• For each series, the first number is an integer N which indicates the number of elements in the series, followed by N integers separated by spaces.

For example:

3
7
4 5 6 5 4 7 8
5
1 2 2 3 4
6
1 2 3 1 2 3

outputFormat

For each series, output a line containing the unique numbers (i.e. numbers that appear exactly once) separated by a single space, in the order they first occur. If there are no unique numbers in a series, output None on that line.

For example, corresponding to the sample input above, the output should be:

6 7 8
1 3 4
None

## sample

3
7
4 5 6 5 4 7 8
5
1 2 2 3 4
6
1 2 3 1 2 3

6 7 8
1 3 4
None

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