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.
['6347', 'q', 'y', 'r', 'T', '8957', 's', 'q', 'F', 'h', 'W', 'm', 'R', 'Y', 'z', 'w', 'h', '7141', '5997', 's']