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.
['K', 'T', '2085', '7083', 'A', 'Q', 'Z', '3779', 'z', 'N', '1319', '3101', '8075', '9407', '2985', 'Y', '1275', '2501', 'p', '2525']