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.
['4693', 'Y', 'u', 'g', '9935', '6995', 'k', 'V', 'B', '3215', '5835', 'n', 'C', 'A', '2047', 'R', 'K', '5611', 'E']