In this task, you are given an input list A. You need to find all the elements of the list that are numbers and calculate their sum.
['f', 's', 'Z', '5015', '1863', 'J', '5345', 'T', '5547', '6067', 'M', '9877', 'g', 'Q', 'O', 'M', '5003', '2623']