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.
['3123', '6669', 'A', '3747', '3195', '8907', 'O', '2081', '8973', '9143', '7511', 'P', 'Y', 'Z', 'Q', 'b', 'h']