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: ['6121', 'S', '8683', 'Y', '6107', 'B', '6193', '5555', '365', '945', '1439', '7257', 'g']
Example Output: 42665

Example Input: ['3683', 'U', 'x', '313', 'n', '3837', '3299', '2081', '2773', 'r', 'O', '257', '6647', '585', 'o']
Example Output: 23475

Example Input: ['6375', 'J', 'X', '9921', 'D', 'z', '4141', 'W', 'b', 'g', '2039', '6605', 'Y']
Example Output:
29081