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: ['K', '4403', 'a', '3881', '4139', 'w', '1861', 'G']
Example Output: 14284

Example Input: ['2039', '1679', '9675', 'S', 'J', '2069', 'r', 'e']
Example Output: 15462

Example Input: ['7597', '9975', 'd']
Example Output:
17572