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: ['7231', '2813', '51', '1745', 'c', 'a', '4929', '3185', '5707', '2095', 'f', 'S']
Example Output: 27756

Example Input: ['901', 'X', 'W', 'D', 'm', 'M', '59', '4855', '6523', 'R', '9781', '8271', '4449', '2221', '8391']
Example Output: 45451

Example Input: ['O', 'B']
Example Output:
0