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: ['V', '2633', '3269', 'r', 'Q', '3517', '2571', 'G', '4105', 'm', 'z', 'B', 'A']
Example Output: 16095

Example Input: ['I', 'J', 'K', 'D', '5961']
Example Output: 5961

Example Input: ['7835', '4627', 't', 'W', '5991', 'd', 's']
Example Output:
18453