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.
['O', '3095', 't', 'k', '6215', '2349', 'e', '5243', '9681', 'E', '3707', 'v', 'O', '3901', '6453', '2979', '9947', 'z']