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:
[169.421, 88.16]

Ex Output:
128.791


Ex Input:
[138.63, 106.759, 86.625]

Ex Output:
110.671


Ex Input:
[108.431, -57.37, 228.857, 229.587, 206.483]

Ex Output:

143.198


