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.
['E', '2053', '5473', '6031', '6731', 'v', 'X', '8325', '1661', '8231', '6943', 'O', 'f', 'Y', 'i', '767', '5955', '6905', 'C', 'L']