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.
['6697', 'j', '1627', 'W', 'e', 'n', 'U', 't', '6527', 'N', 'o', '5553', 'a', 'H', '3585', 'e', 'y', 'N', '1577']