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: ['s', '3607', 'p', 'P', '9285', 'J', 'l', '9863', '9823', '2817', 'g', '9751', '599', '2605', 'k', 'Y', 'O', 'U', '9649']
Example Output: 57999

Example Input: ['G', 'Z', '4819', '9763', '9987']
Example Output: 24569

Example Input: ['7123', 'P', 'a', '401', '543', '6521', 'j', 'k', '7599', '3873', '733', 'i', '9575', 'G']
Example Output:
36368