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', 'y', '9053', 'G', 'U', 'j', '7377', '2749', '5289', '5419', 'y', '6667', '987', '3009', 'm', '4989', '6105', '6415', '7633']