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', '41', 'r', '8211', '9085', 'F', 's', 'w', 'k', 'r', '6705', 'f', 'G', 'J', 'h', '3327', 'b', '969', '3313']