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: ['29', 'N', '5061', '7191', 'z', '8367']
Example Output: 20648

Example Input: ['Q', '8317', '8989']
Example Output: 17306

Example Input: ['y', 'p', '3553', '2155', 'b', 'R', 'j', 'V', 'U']
Example Output:
5708