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: ['c', 'E', 'M', '1303', 'y', 'H']
Example Output: 1303

Example Input: ['Y', 'X']
Example Output: 0

Example Input: ['6641', '9309', 'v', 'P', '3931']
Example Output:
19881