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: ['339', 'h', 'd', '7449', 'e', 'u', '5055', '7029', '9009', 'G', 'U', '3', '441', '3273', 'K', '3827', '7069', 'x']
Example Output: 43494

Example Input: ['8207', '4791', '3925', 'b', 'Z', '8471', '9215', '3117', 'p', '9095', 'h', 'k', 'E', 'h', '6047']
Example Output: 52868

Example Input: ['L', '3803', 'r', 'b', '2037', 'A', 'H']
Example Output:
5840