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: ['X', 'f', 'p', 'R', 'N']
Example Output: 0

Example Input: ['1671', 'H', '9271']
Example Output: 10942

Example Input: ['9715', 'G', 'p', 'F', 'O', '1169', 'D', '9899', 'u', 'B', 'm', 'G', 'D', 'd', '233', 'g', '3039', 'k', '9985']
Example Output:
34040