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.

['R', 'I', 'f', 'K', 'p', '8579', 'e', '1223', 'I', 'K', '8311', '2147', '4241', 'z', '6671', 'r']
31172

['D', '1693', 'f', 'B', 'o', '3947', '8667', 'f', '6721', '4191', '79']
25298

['6313', 'X', 'p', '8075', 'c', 'A', '6055', '6753', 's', 'd', 'q', '1537']

28733