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.
['C', 'y', '5001', 'x', '2055', 'e', 'W', 'j', '8603', '1251', '7785', '7183', 'E', '7909', '9383', 'X', 'k', '9469']