Migrated from Lutece 387 Day Day Bath

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Description

Bathing is a normal thing for the students in SCU.But for a school like SCU, too many students ,too little Bathroom. xy is a bathing-like girl. So she bathes everyday. However, with so many students waiting to bathe, it's a time-wasting thing to bathe. Now there are many students before her waiting to bathe .How long must her wait?

Input

The first line is an integer $T$ for test cases.

For every test case, the first line of an input contains two integer $n$ and $m$ ($n$ for the number of students before her ($0\leq n\leq 10^5$), $m$ for the number of shower positions ( $1\leq m\leq 10^5$) )

The next $n$ lines contain numbers $t_i$(the bathing time for the $i_{th}$ person, $5\leq t_i\leq 90$), one number per line.

Assume it takes no time to come in or out.

Output

The output file contains $T$ lines ,each for one test case.

Each line contains one number, the time before her turn.

If the time is greater than $600$, print -1.

Samples

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Note

The data used in this problem is unofficial data prepared by pfctgeorge. So any mistake here does not imply mistake in the offcial judge data.

Resources

9th SCU Programming Contest Final