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: ['J', 'S', 'S', 'U', 'w', '7691', '7529', 'B', '3861', '4557', 'd', '569', '1547']

SOLUTION: 25754

PROBLEM: ['J', '5149', 'H', 'L', 'm', 'h', '3863', 'n', 'z']

SOLUTION: 9012

PROBLEM: ['Y', '1219', '2963', 'n', 't', '1395']

SOLUTION:
5577