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.

Example Input: ['4811', 'Q', '2289', 'N', 'I', '7681', 'z', '8179', '3359', '5299', 'R', 'z', '8697', '5781', '4803', '2715', '6511', '1371']
Example Output: 61496

Example Input: ['8669', '9115', '2573', '9261']
Example Output: 29618

Example Input: ['4755', 'F', 'o', '8643', 'q', '757', 'O']
Example Output:
14155