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: ['57', '9977', '2657', 'p', '9573', '7745', '4755', 'U']
Example Output: 34764

Example Input: ['A', '9979', '8723', '1131', 'i', 'p', 'M']
Example Output: 19833

Example Input: ['3469', 'n', '5561', '8597', '921', '4737', 'r', 'P', '7127', '3651', 'D', '1703', 'y']
Example Output:
35766