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.
['B', 'E', 'N', 'f', '6385', 'Q', '4135', '6417', '4203', '7497', 'C', 'y', '4235', '3319', '1939', '629', 'A', '5689', '7599', 'D']