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

Example Input: ['x', '5259', 'T', 'L', 'C', 'H', '2493', 'u', '3851', '2439', 'U']
Example Output: 14042

Example Input: ['A', '3849', '9981', '7567']
Example Output:
21397