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

Example Input: ['1057', '3937']
Example Output: 4994

Example Input: ['7509', '6563', 'f', '2413', 'y', 'L', '3913', '4941', 'f', '6231', '941']
Example Output:
32511