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: ['89', '5965', '9463', 'k']

SOLUTION: 15517

PROBLEM: ['7831', 'O', '6017', 'v', 'U', '5761', 'Q', 'Q', 'w', '8465', 'Z', 'P', 'i', 'u', '1635', 'n', '8471', '4213']

SOLUTION: 42393

PROBLEM: ['4039', 'i', '1685', 'O', 'n', '471', 'j', '349', 'v', '8403', 's', '7619', 'n']

SOLUTION:
22566