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.
['z', 'v', 'Q', '8673', '5589', 'U', '2167', 'Y', 'r', 'E', '5365', 'L', '7041', 'f', 'k', 'm', 'A', 'g', '8779']