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.
['E', '2839', '4327', 'w', '6841', 'p', '555', '5781', 'X', 's', '3269', '1285', 'y', '4695', 'a', '7193', 'G', '1307']