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: ['R', '9751', '4367', 'l', 'N', '5125', '8751', '7507', 'y', 'K', '6127']
Example Output: 41628

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

Example Input: ['X', 'm', 'U', '3395', 'A', '697', 'v', 'U', 'p']
Example Output:
4092