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: ['3351', '6445', 'Y', '8455', 'V', 'z', 'a', 'V', 'S', '8551', '4101', 'q', '8743', '5999', '7155', '3825', '2241', '9957']

SOLUTION: 68823

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

SOLUTION: 46440

PROBLEM: ['481', '5283', '2919', 'd']

SOLUTION:
8683