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: ['A', '9775', '5867', 'n', '1329', '5973']
Example Output: 22944

Example Input: ['7669', '3367', 'A', 'Z', '6173', '4391', 'f', 'S', '9657', '2631']
Example Output: 33888

Example Input: ['z', 'f', '5799', 'k', '3195', 'v']
Example Output:
8994