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.
['9975', '2649', '3499', 'n', '7621', '8205', 'J', 'I', 'E', 'O', 'P', 'q', '2235', 'B', 'v', 'B', '9777', '9651', 'G', 'N']