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', '6403', '4077', '9243', '3139', 'a', '8323', 'w', '2395', '6913', 'W', 'V', '1665', 'e', 'o', '9475', '8653', '8825', 'p', 'L']