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: ['6731', 'f', '4561', '5601', 'i']
Example Output: 16893

Example Input: ['V', '2633', '3269', 'r', 'Q', '3517', '2571', 'G', '4105', 'm', 'z', 'B', 'A']
Example Output: 16095

Example Input: ['1731', 'W', '1825', 'B', 'N', '2153', '5577', 'W']
Example Output:
11286