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: ['x', 'd', '5121', 'I', '6737', '3789', '6167', 'C', '8947', 'k', '4715', '1885', 'H', 'B', '5685', 'S', '4615', 's', '7709']

SOLUTION: 55370

PROBLEM: ['3873', 'D', 'J', '2799', 'k', 'F', 'I', '3457', '5647', '4815', '7509', 'Y', '1251', '2211']

SOLUTION: 31562

PROBLEM: ['w', 'z', '637', '8871', '779', 'j']

SOLUTION:
10287