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CF2164B.Even Modulo Pair
Even Modulo Pair
You are given a strictly increasing sequence of positive integers . Find two distinct elements and from the sequence such that and is even, or determine that no such pair exists.
denotes the remainder from dividing by .
Input
Each test contains multiple test cases. The first line contains the number of test cases (). The description of the test cases follows.
The first line of each test case contains one integer () — the length of the sequence.
The second line of each test case contains integers () — the given sequence.
It is guaranteed that the sum of over all test cases does not exceed .
Output
For each test case:
- If no such pair exists, output
-1. - Otherwise, output two integers and — the elements that satisfy the condition.
If there are multiple valid pairs, you may output any of them.
Note
In the first test case, choosing and yields , which is even.
In the third test case, it is clear that no valid pair exists.
Samples
4
5
1 3 4 5 6
6
2 3 5 7 11 13
4
2 3 13 37
3
17 117 1117
3 5
3 11
-1
17 1117
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