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: ['W', '3561', '4631', '8379', 'W', '6857', '2723', '5393', 'h', 'g', 't', 'I', 'R', '2321', 'l']
Example Output: 33865

Example Input: ['7771', 'g']
Example Output: 7771

Example Input: ['9409', 'p', 'S', 'T', '6663', 'I', 'E', '6795', '345', 'v', '4547', 'J', '6447', 'k', '8349']
Example Output:
42555