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: ['w', '7301', '9411', 'z', 'g', 'X', '1045', 'l', 'F', 'M', 'R', '7957', 'e', '5145']

SOLUTION: 30859

PROBLEM: ['9879', 's', '4233', '1147', 'd', 'D', '2367', '7069', '4831']

SOLUTION:
29526