TASK DEFINITION: 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.
PROBLEM: ['i', 'C', '5373', '2017', 'm', '5435', 'Y', 'h']

SOLUTION: 12825

PROBLEM: ['B', 'K', '9399', 't', '5541', 'w', '1939', '7841', 'q']

SOLUTION: 24720

PROBLEM: ['C', '1993', '9763', '3773', '6183']

SOLUTION:
21712