Sumo GG is very popular in the laboratory. Many people come to ask Sumo GG for questions.

Now there are n people in line to ask him for advice, as the time for i-th people to ask him questions is . In order not to affect everyone's lunch, please line up for n people so that the average waiting time of n people is the minimum.

输入描述:

The first line contains  — the number of test cases.

For each test case, the first line contains a single integer , the number of people waiting for asking a question. 

The next line contains n integers , the time of  people required to ask a question.

输出描述:

For each of the test cases, output a single integer, the minimun average waiting time of n people (accurate to two decimal places).

2
1
5
10 
56 12 1 99 1000 234 33 55 99 812

0.00
291.90