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.
['H', '2235', 'b', 'l', 'J', 'v', 'V', '9807', '213', '2449', '537', '5919', '7115', 'V', 'w', 'a', 'x', '7615', '1771']