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.

['K', '5815', 'E', 'c', '7379', '4995', 'w', 'B', 'j', '6227', 'B', '733', '1491', '3191', '9413', '2751', 'O', 'J', '6239', '3521']
51755

['6001', '6423', '5591', '8721', 't', 'x', '3723', 'E', 'F', '7353', 'b']
37812

['8581', 'X', 'b']

8581