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.
['669', 'v', '8109', 'V', 'l', '1405', 'e', '2739', '1387', 'J', 'h', 'X', '1273', 'O', '8073', '2223', 'b', 'I']