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: ['6019', '1467', '3415', '7785']
Example Output: 18686

Example Input: ['7293', '2619', '2459', '3829', 'J', 'c', 'a', 'a', '311', 'x', 'r', '6123', '2847', '4809']
Example Output: 30290

Example Input: ['u', '6809']
Example Output:
6809