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.
['b', 'E', '2455', 'T', '8601', '8837', '8485', '6105', 's', '9925', '4183', 'z', 'a', 'q', 's', 'e', 'R', 'S', 'T', 'C']