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: ['G', 'e', 'R', '4427', '3401', '3065', 'I', '2781', '6829', '5261']
Example Output: 25764

Example Input: ['u', 'i', 'z', 't', '9617', 'd', '3255', 'w', 'S', '3041', '7451']
Example Output: 23364

Example Input: ['6865', '2439', '6747', '9785', 'a', '9453', 'K', '6275', 'Z', '6517', 'j', '8283', '4399', 'O', '6545', '6263', '2785', '4625']
Example Output:
80981