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.
['2275', '4057', '2645', '2865', '2681', '4065', 'd', 'Y', '2155', 'l', '4151', 'l', 'r', '5353', 'V', '3001', 'n', 'd', '6673']