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.
['2469', 'c', '6931', 'a', '2167', '9493', '9403', '4123', '4949', 'R', 'V', 'h', '315', 'T', '9411', 'M', '1329', '8217', '6105', 'Y']