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.
['2591', 'q', 'h', '5759', '6559', '311', 'T', '9013', 'b', '4253', 'M', '693', 'C', '4215', '7487', 'M', 'K', 'H']