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: ['3145', 'C', '7725', 'k', 'z']
Example Output: 10870

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: ['X', 'b', 'x', 'X', '7443', 'g', 'd', 'x', 'y', '9963', 'a']
Example Output:
17406