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: ['a', 'f', '2185', 'N', '6381', '6429', '7499', 'd', '757', 'k', 'k', 'b', 'N', '2697', 'A', '8037']
Example Output: 33985

Example Input: ['j', 'R', '2435']
Example Output:
2435