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.
['I', '7513', 'K', '259', '9885', 'x', '1823', '3557', 'p', 'p', '599', 'E', '7833', '9761', '2393', '717', 's', 'b', 'V', '8419']