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: ['M', '1589', '8353', 'X', 'P', '3173', 'V', '1335', 'm', 'l', '6421', '4823', 'r', '8941', '4255', '9107', 'z', '2449', '2321', 'l']
Example Output: 52767

Example Input: ['a', 'm', '3205', '1869', '1117', 'K', '5785']
Example Output: 11976

Example Input: ['8595', '1935', '1395', 'L', 'F', 'Y', '7003', 'A', '9619', 'm', '7493', '6021', 't', '2173', 'L', '3177']
Example Output:
47411