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', 'J', 'z', 'o', '1121', '7247', '8987', 'u']
Example Output: 17355

Example Input: ['9125', '1443', '2303', 'O', '8463', '401', '3983', 'g', '4327', 'z', 'n', 'F', 'Q', 'j', '9885']
Example Output: 39930

Example Input: ['2533', '8859', '553', '7379']
Example Output:
19324