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.
['z', '4855', 'H', '4327', 'S', 'E', '9635', '2931', 'V', '5481', 'e', '4881', '3033', '5309', '9759', '9909', '6949', 'o']