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', '1951', '8905', '1591', '5463', 'C', 'F', 'l', '9629', '2713', '2881', 'b', '4119', '8151', '1979', 'F', 'F', 's', '8829', '5009']