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:
[57.506, 172.357, 191.473, 131.849]

Ex Output:
138.296


Ex Input:
[199.728, -96.25, -77.714]

Ex Output:
8.588


Ex Input:
[98.452, -17.106, -19.888]

Ex Output:

20.486