Give nnon‑negative integers, please find the least non‑negative integer that doesn’t occur in the nnumbers.

The first line is an integer T, representing the number of test cases.
For each test case:
The first line of each test case is an integer n.
The second line of each test case are nnon‑negative integers a _i .
( T ≤ 10, n ≤ 2 × 10 ⁵ , 0 ≤ a _i < 2 ³¹ )

for each test case, output a line with the answer

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