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

SOLUTION: 16152

PROBLEM: ['6001', '6423', '5591', '8721', 't', 'x', '3723', 'E', 'F', '7353', 'b']

SOLUTION: 37812

PROBLEM: ['2173', '2551', '797', 'h', '5943', 'H', 'I', 'A', 'U', 'W', 'm', 'W', '9143', 'r', '7799', '3895', 'G', 'D', '4013']

SOLUTION:
36314