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: ['3883', 'T', '6175', 'B', '4365', '3719', 'V', 'B', '3173', 'K', 'Z']
Example Output: 21315

Example Input: ['B', 'K', '9399', 't', '5541', 'w', '1939', '7841', 'q']
Example Output: 24720

Example Input: ['4131', 'u', '6489', '9017', 'F', 'T', 'f']
Example Output:
19637