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.
['1897', 'v', '9045', '1171', '5621', '8671', 'V', 'D', 'A', 'V', 'U', 'x', '6969', 'K', 'G', '3827', '6963', 'B', 'q', '3113']