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: ['6867', 'x', '8481', '5091', '979', 'a', 'S', 'i', 'd', '1591']
Example Output: 23009

Example Input: ['2485', 'Q', 'G', '5533', 'Y', '21', 'D', 'S']
Example Output: 8039

Example Input: ['7149', '367', 'g', '9605', 'S', 'D', 'U', '4381']
Example Output:
21502