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.
['4423', 'Q', '5353', '4591', '1703', '4337', 'G', 'j', '2263', '2123', '6025', 'O', 'L', 'N', '1091', '9059', '8117']