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: ['K', '4403', 'a', '3881', '4139', 'w', '1861', 'G']
Example Output: 14284

Example Input: ['h', 'a', '1645', '2391', '759', '519', '3331', '2831', '3427', '9893', 'u', 'J', '7391', '8379', 'V']
Example Output: 40566

Example Input: ['8363', 'C', 'X', 'y', '2503', '4649', 'R', '9817']
Example Output:
25332