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: ['89', '5965', '9463', 'k']
Example Output: 15517

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

Example Input: ['3177', '3217', '3449', '8965', 'O', 'r', '5337', '7461', 'M']
Example Output:
31606