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: ['W', 'H', 'k', 'L', '2425']

SOLUTION: 2425

PROBLEM: ['s', '425', '6135']

SOLUTION: 6560

PROBLEM: ['B', 'u', '3253', 'm', '6345', 'C', '3581', 'd', 'H', 'S', '5553', '8681', '6489', 'N', '4815']

SOLUTION:
38717