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.
['5277', 'o', '8841', '8073', '7393', 'h', 'A', 'l', '121', '1499', '8761', '35', 'g', 'r', 'D', '9257', '2833', '8035', '9745', 'A']