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.
['D', '1831', '1129', '2855', 'h', 'J', 'B', '1373', 'm', '7225', 'T', '3063', '5011', 'q', 'd', '2525', 'J', '8525', '5975']