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: ['K', '4403', 'a', '3881', '4139', 'w', '1861', 'G']

SOLUTION: 14284

PROBLEM: ['2175', '4539', 'L', 'T', 'q', '2407', 'F', 'V', 'b', '9475', '2279', '4469', '6231']

SOLUTION: 31575

PROBLEM: ['6057', '3743', 'n', 'M']

SOLUTION:
9800