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: ['1305', '1673', 'w']
Example Output: 2978

Example Input: ['5095', '8235', '4901', 's', '4177', '3077', 'l']
Example Output: 25485

Example Input: ['5481', 'R', 'L', 'V', '4429', 'E', '1247', 'z']
Example Output:
11157