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', '8019', 'e', 'S', 'C', '6565', '3231', '3115', 'I', '4077', '637', '3995', '9297', 'U', 'c', 'p', 'n', '527']