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.
['V', 'K', 'd', 'z', 't', 'I', '55', '3217', 'x', 'g', '9459', 'W', 'Q', '8159', 'n', '1533', '2023', 'S', 'c', 'D']