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: ['4869', 'L']
Example Output: 4869

Example Input: ['4749', '1169', '4273', 'X']
Example Output: 10191

Example Input: ['h', '1157', 'm', '8975', '6165', '7491', '1855', '3489', '9629', '631', '9641']
Example Output:
49033