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.
['6003', '6513', 'm', 'o', '9177', 'z', 'Z', '165', '1451', 'A', 'B', '7515', '487', '2089', '3989', 'b', 'M', '1363', 'S']