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: ['2729', 'W', 'i', '9073', '343', 'j', '2329', '9159', '4825']
Example Output: 28458

Example Input: ['2787', 'z', '9351', '3339']
Example Output: 15477

Example Input: ['8509', 'v']
Example Output:
8509