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', 'J', 'z', 'o', '1121', '7247', '8987', 'u']
17355

['9125', '1443', '2303', 'O', '8463', '401', '3983', 'g', '4327', 'z', 'n', 'F', 'Q', 'j', '9885']
39930

['I', '5119', 'X', 'c', '7517', 'W', '2693', 'W', 'A', 'g', 'C', '3987', '1079', 'W', 'b', 'A', '3415']

23810