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.
['6563', 'F', 'J', 'q', '969', 'H', '2649', 'o', 'i', 'k', 'y', 'I', '3071', 'v', '1341', '9439', 'K', 'P', '1773', '3609']