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.
['5197', '5923', '4337', '3095', 'L', '7707', 'W', '4387', '515', 'e', '5367', 'a', 'A', 'T', '6489', '2703', '5933', 'p']