Second Largest Unique Value

You are given several test cases. For each test case, you are given an integer N followed by a list of N integers. Your task is to find the second largest unique value in the list. If the list has less than two distinct numbers, print -1.

Let \( S \) be the set of distinct numbers in the list. The condition for a valid answer is \( |S| \ge 2 \). If \( S = \{ s_1, s_2, \ldots \} \) sorted in descending order, then your answer is \( s_2 \).

inputFormat

The first line of input contains a single integer T representing the number of test cases. For each test case:

1. The first line contains an integer N, the number of elements in the list.
2. The second line contains N space-separated integers.

outputFormat

For each test case, output a single line containing the second largest unique integer in the list. If no such value exists, output -1.

## sample

1
5
4 2 1 3 2

3

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