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.
['2991', '8459', 'x', 'j', 'O', '5747', '9381', '6485', 'J', 'z', '9151', '7497', 'j', '3079', '2425', '1017', '9507']