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: ['3705', '9217', 'C', '4609']
Example Output: 17531

Example Input: ['4271', 'N', 'M', '5239', '7037', 'x', 'U', 's', '7107', '4163', 'f', '3607', '6155']
Example Output: 37579

Example Input: ['h', '2593', '6381', '2429', 'v', '6407', '281', '6881', '6565', 'f', 'v', 'h', 'M', 'I', '839', 'D']
Example Output:
32376