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: ['1875', '9833', 'i', '7493', 'J', 'P', 'z']
Example Output: 19201

Example Input: ['6921', 'a', 'U', '2821', '2111', 'h', '3937', '3697', 'd', '6309', 'q', '7961', '5287', '5375', '2721', '4523', 'V', '8633', 'c', '7643']
Example Output: 67939

Example Input: ['6395', '8005', 'j', 'S', 'q', 'I', '4999', 'g', 'g', '6913', 'f', 'j', '2589', 'e', '3883', '4755']
Example Output:
37539