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: ['9403', 'u', '4159', 'w', '3467']

SOLUTION: 17029

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

SOLUTION: 46440

PROBLEM: ['W', 'H', '9545', '4325', 'S', 'd', 'r', 'F', 'u', '4881', 'h']

SOLUTION:
18751