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.
['A', '9785', '1739', 'x', '2389', 'O', 'J', '1407', '9067', 'x', '9747', '2485', '4631', '6021', '4077', '2779', 'V', '2449', '7401']