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: ['t', '7469', 'Y', 'N', '8137']

SOLUTION: 15606

PROBLEM: ['w', '8035', 'J', '2671', '7509', '1573', '6915', '8569', '345', 'T', 'P', 's', '1341', '7823', '8671', 'm', 'Q', 's', 'N']

SOLUTION: 53452

PROBLEM: ['E', '2143', 'u', 'V', '4145', 'V', 's', 'a', '405', 'i']

SOLUTION:
6693