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.
['5815', '9839', 's', 'B', 'B', 'q', 'h', '273', 'I', 'O', '607', '7437', '3535', '4533', 'S', 'a', '9529', '6113', 'v']