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.
['g', '7909', '4899', '7855', '1373', '4233', 'T', 'K', 'X', 'k', '9849', '9985', '1809', '5323', '9569', 'h', 'G', 'C', 'w']