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: ['D', 'K', 'n', 'd', 'i', 'U']
Example Output: 0

Example Input: ['89', '5965', '9463', 'k']
Example Output: 15517

Example Input: ['l', '9427', 'n', '9079', 'J', 'c', 'Z', 'c', '2923']
Example Output:
21429