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.
['W', '6287', 'D', '1165', 'N', 'k', 'g', 'Y', 'A', 'm', '2541', 'm', 'W', '9927', 'D', 'K', '5865', '3553', '5223']