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: ['C', '9973', 'b', '693', 'y', 'H', 'C', 'P', 'b', 'J', 'f', 'T', '2317', 'O', '5755', '8201', 'p', 'y', '8721', 'i']

SOLUTION: 35660

PROBLEM: ['3683', 'U', 'x', '313', 'n', '3837', '3299', '2081', '2773', 'r', 'O', '257', '6647', '585', 'o']

SOLUTION: 23475

PROBLEM: ['u', 'e', 'P', 'D', '255', '2573', 'E', 'P', 's', '3725', '3391', 'I', '5323', '885']

SOLUTION:
16152