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.
['3565', 'z', '8811', 'z', 'U', '113', 'I', '1307', '135', 'V', 'P', '5183', '2505', '4863', '1113', 'A', '7575', '827', 'B']