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.
['267', '315', 'e', 'l', '2331', 'x', '3973', '7295', '1805', 'O', 'Y', 'H', '2649', '5593', 'W', '65', '5227', '1279']