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.
['J', '8081', '2649', '6223', 'y', 'X', 'r', 'E', '6241', '8365', 'i', '7827', 'N', 'B', '8409', 'U', '7141', '2953']