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', 'y', '4891', '1539', 'J', '5737']
Example Output: 12167

Example Input: ['3433', '6955', 'Q', 'E', '3557', 'S', '2931', '9879', 'S', 'f', 'Q']
Example Output: 26755

Example Input: ['l', 'd']
Example Output:
0