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: ['L', 'i', '9225', 'w', '5365', '8077', '2733', 'W', '8493', 'B']
Example Output: 33893

Example Input: ['Q', '8317', '8989']
Example Output: 17306

Example Input: ['2879', '9375']
Example Output:
12254