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', '1335', 'G', 'h', '6729', '1999', 'u', 'I', 'r', 'm', '4757', 'W', '3715', '701', '1999']

SOLUTION: 21235

PROBLEM: ['D', '5207', 'E', '119', 'g', '2991', 'G', 'g', 'u']

SOLUTION: 8317

PROBLEM: ['2569', 'V', '1025', '4965', 'k', 'W', '3755']

SOLUTION:
12314