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: ['Z', 'w', 'M', '2233', '5275', '5277', 's', '971', '7085', '6259', 'V', 'E', '4923', '7365', 'c', 'd', 'c', 'U', 'P']
Example Output: 39388

Example Input: ['5909', '3811', 'Q']
Example Output:
9720