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: ['X', '989', 'U', '9551', '6385', 'Y', '1433', 'J', '1833', '685', 'u']
Example Output: 20876

Example Input: ['b', 's', 'v', '4757', '9063', 'I', '8397', '7975', 'Q']
Example Output: 30192

Example Input: ['M', 'r', '5805', 'I', '1209', '5115', '6091']
Example Output:
18220