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: ['2585', '3043', 'w', '7697', '53', 't', 'A']
Example Output: 13378

Example Input: ['o', 'a', 'K', '6031']
Example Output: 6031

Example Input: ['Q', '7407', 'K', 'D', 'b']
Example Output:
7407