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: ['X', 'P', 'x', '9471', '5', 'c', 'f', '5077', '1085', '2267', 'R', 'q', '4987', '9529', 'H', 'n', 'r', 'u']
Example Output: 32421

Example Input: ['f', 'F', 'E', '2279', 'r', '6419', 'd', 'M', '3975', '3797', '9201', 'F', 'c', '4753', '959', 'v', '8963', '4007']
Example Output: 44353

Example Input: ['5601', '661', '5449', '3723']
Example Output:
15434