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: ['7293', '2619', '2459', '3829', 'J', 'c', 'a', 'a', '311', 'x', 'r', '6123', '2847', '4809']
Example Output: 30290

Example Input: ['p', '4689']
Example Output: 4689

Example Input: ['275', 'w', 'N', 'F']
Example Output:
275