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.
['D', 'g', '1845', 'e', 'z', '3457', 'e', 'G', 'P', 'i', 'e', '8983', 'U', 'c', 'A', 'I', '6371', '8443', '1683', 'd']