#描述#
It is said that 90% of frosh expect to know average in their class. You are to provide a reality check.

#格式#
##输入格式##
The first line of standard input contains an integer C, the number of test cases. C data sets follow. Each data set begins with an integer N, the number of people in the class (1 &lt= N &lt= 1000). N integers follow, separated by spaces or newlines, each giving the final grade (an integer between 0 and 100) of a student in the class.

##输出格式##
For each case you are to output a line giving the average of their class, rounded to 3 decimal places.

#样例1#
##样例输入1##

1
3 1 2 3

##样例输出1##

2.000

#限制#
1000ms
32768KB

#提示#

#来源#
Lily