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.
['Z', 'w', 'M', '2233', '5275', '5277', 's', '971', '7085', '6259', 'V', 'E', '4923', '7365', 'c', 'd', 'c', 'U', 'P']