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', '4991', '7289', '4355', 'I', '8415', '5175', '5329', 'G', 'a', '7193', 't', '8821', 'j', '7239', '405', 'y', 'O', '9881', 'w']
Example Output: 69093

Example Input: ['k', 'a']
Example Output: 0

Example Input: ['5451', '1701', '9357', '5509', 'Y', 'r']
Example Output:
22018