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.
['d', 'o', '8189', '3877', '9191', 'q', '1495', 'r', 'b', '459', 'b', 'i', '7701', '4907', 'r', 'R', '6317', '9085']