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.
['W', '8593', '9427', '9931', '8919', 'X', 'B', '8861', '1933', 'Z', 'V', '3427', 'S', '8717', 'd', '1593', '7659', 'Q', 'n']