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.
['9235', '8719', 'X', '6589', 'c', '4705', '1419', '999', 'R', 'm', 'v', '1547', 'o', '8019', '527', '7527', '6857', 'q', 'j']