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:
[172.084, 126.948, 90.757]

Ex Output:
129.93

Ex Input:
[-47.309, -46.076, 191.14, -6.032, 4.858]

Ex Output:
19.316

Ex Input:
[51.048, 4.433, 18.504]

Ex Output:
24.662