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.

Ex Input:
[21.007, 48.739, -49.831, -22.699]

Ex Output:
-0.696


Ex Input:
[151.151, 144.049, 217.252]

Ex Output:
170.817


Ex Input:
[9.749, 164.453]

Ex Output:

87.101


