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.
['5885', '5241', '3877', 'W', 'L', 'c', 'b', '1125', 'C', '2541', 'q', 'd', '9517', 'u', '2001', 'o', 'Z', 'F', '1849', '575']