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.
['8773', '2237', '265', '1323', '6541', 'w', '9765', '5143', '8629', '4789', '4963', 'p', '5085', 'D', '6075', '3085', 'b', '7381', 'D', 't']