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.
['C', '2715', '9335', 'r', 'l', 'd', 'T', '7707', 'I', 'f', 'z', 'M', 'E', '9713', 'h', 'm', 'S', 'V']