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: ['9787', '1491', '4411', '5261', 'U', '9787', 'b']
Example Output: 30737

Example Input: ['3451', '2325', '2511', 'i', '6159', '2291', 'e', 'l', 'P', '1177', 'o', 'T']
Example Output:
17914