In this task you will be given a list of numbers and you need to find the mean (average) of that list. The mean of a list can be found by summing every number in the list then dividing the result by the size of that list. The output should be rounded to 3 decimal places.

[-81.785, -44.121]
-62.953

[215.561, -18.128]
98.716

[154.587, 123.531]

139.059