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: ['8871', '1297', 'W', 'f', 'Y', '8731', '113', '6707', '379', '9631', 'X', 'C', 'q']
Example Output: 35729

Example Input: ['Y', 'X', 'd', 'N', '1877', '2865', 'M', '1249', '9385', 'v', 'o', 'P', 'P', '6029']
Example Output: 21405

Example Input: ['8821', '7221']
Example Output:
16042