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: ['507', 'P', '9697', 'u', '5057']
Example Output: 15261

Example Input: ['D', '9679', 'e', '5537', 'G', 'l', '2653', 'a', 'Y', '8467', 'q', 'L', '7239', 'O']
Example Output: 33575

Example Input: ['4405', '2569', 'y', '1875', 'K', 'j']
Example Output:
8849