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: ['J', 'S', 'S', 'U', 'w', '7691', '7529', 'B', '3861', '4557', 'd', '569', '1547']
Example Output: 25754

Example Input: ['b', '5447', 'R', '8489', 'L', '627', 'P', '7491', 'c', 'c', 'r', '6923', '1167']
Example Output: 30144

Example Input: ['z', 'z', 'F', '7243']
Example Output:
7243