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: ['L', 'w', '2783', '6993', 'd', '9173']

SOLUTION: 18949

PROBLEM: ['4437', '1265', '1519', 'K', 'Q', 'b', 'n', 'J', '6631', 'K', 'q', 'D', 'U', 'u', '3653', '5169', 'L', 's']

SOLUTION: 22674

PROBLEM: ['G', 'H', 'g', '3851']

SOLUTION:
3851