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: ['7361', '6913', '3605', '2081', '7619']
Example Output: 27579

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: ['P', 'M', '8451', '7711', 'b', 'u', '5091', '6621', 'Q', 'w', '795', '6541', '6631', 'q', '9681', '2235', '7581', '2563']
Example Output:
63901