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: ['W', '3561', '4631', '8379', 'W', '6857', '2723', '5393', 'h', 'g', 't', 'I', 'R', '2321', 'l']

SOLUTION: 33865

PROBLEM: ['Q', '2271', '1803', '2363']

SOLUTION: 6437

PROBLEM: ['y', 'u', 'n', 'y', '9247', 'S', '2473', 'O']

SOLUTION:
11720