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: ['j', 'R', '2435']
Example Output: 2435

Example Input: ['x', '5259', 'T', 'L', 'C', 'H', '2493', 'u', '3851', '2439', 'U']
Example Output: 14042

Example Input: ['5665', 'w', '7573', 'g', 'N']
Example Output:
13238