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.
['v', '4905', '711', 'O', 'i', 'F', 'G', '9207', '6411', '4901', 'l', 'L', 'B', 'C', 'O', 'X', 'R', 'd']