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.
['9141', 'a', '2275', '1755', '5437', 'e', 'g', 'o', 'k', '2221', 'b', '7701', 'D', '7453', 'B', 'Y', '1593', '9827']