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: ['4701', 'b', 'i', 'B', 'z', '7837', 'W']
Example Output: 12538

Example Input: ['89', '5965', '9463', 'k']
Example Output: 15517

Example Input: ['685', 'Q', 'j', '9403', 'a', 'T', 'L', '8469', '2465', '7661', 'G', '2289', '8905']
Example Output:
39877