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: ['f', 'N', '8597', 't', 'K', '9755', 'j', '9747', '7259', '5493', 'n', '7269', '8493', '2279', '5369', 'f']

SOLUTION: 64261

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

SOLUTION: 53452

PROBLEM: ['3407', '3339', '9703', '9133']

SOLUTION:
25582