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.
['Y', 'G', '1933', '8485', 'n', '9611', 'C', '8641', 'm', '7649', '8595', 'h', '7863', 'B', 'I', '9185', 'H', '8197']