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: ['2871', '1337', '3771', '4671', 'l', '3785', 'V', 'z', 'R', 'u', '6097', 'R', '4297', 'd', '6339', 'Y', 'V', '5873', '7399']

SOLUTION: 46440

PROBLEM: ['m', '3481']

SOLUTION: 3481

PROBLEM: ['6921', 'a', 'U', '2821', '2111', 'h', '3937', '3697', 'd', '6309', 'q', '7961', '5287', '5375', '2721', '4523', 'V', '8633', 'c', '7643']

SOLUTION:
67939