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: ['8529', '2657', '1599', 'b', '8187', '7005', '7481']
Example Output: 35458

Example Input: ['887', '8133', 'X', '2253', '8461', 'I', '5425', 'Z', 'z', 'r']
Example Output: 25159

Example Input: ['57', '9977', '2657', 'p', '9573', '7745', '4755', 'U']
Example Output:
34764