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: ['D', 'P', '9951', '2897', 'V', 'C', 'B', 'H', 'c', 'h', '2843', 'a']
Example Output: 15691

Example Input: ['4529', '7465', 'S', 'Z', 'v', 'w', '5791', '3363', '2643']
Example Output: 23791

Example Input: ['1307', '9961', '9927', '6041', '4627', 'U']
Example Output:
31863