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: ['2175', '4539', 'L', 'T', 'q', '2407', 'F', 'V', 'b', '9475', '2279', '4469', '6231']
Example Output: 31575

Example Input: ['Q', '1669']
Example Output: 1669

Example Input: ['G', '4799', '3131', '941', '697', 's', 'w', '9613', '5541', 'P', '8539']
Example Output:
33261