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.
['F', '7227', 'A', '4871', 'R', '1661', '7333', 'z', 's', 'O', 'b', 'T', 'E', '4813', 'U', 'Z', '9215', 'A']