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: ['D', 'P', 'y', '4891', '1539', 'J', '5737']

SOLUTION: 12167

PROBLEM: ['187', 'J', 'l', 'p', '1009', 'g', '5817', 'V', 'B', 'Z', '3329', '9253']

SOLUTION: 19595

PROBLEM: ['Q', '8317', '8989']

SOLUTION:
17306