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: ['X', 'P', 'x', '9471', '5', 'c', 'f', '5077', '1085', '2267', 'R', 'q', '4987', '9529', 'H', 'n', 'r', 'u']
Example Output: 32421

Example Input: ['D', 'b', 'h', 'p', '1637']
Example Output: 1637

Example Input: ['1785', '9999', '5211', '1387', '2507', 'G', 'f', 'M', '5963', '5729']
Example Output:
32581