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.
['8709', 'u', 'E', '5711', '3625', '6127', 'h', '4579', '5357', 'D', '8355', 'x', 's', '4197', '4077', 'I', '4153', '8067', 'b']