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: ['4159', 'H', 'h', 'W', 'w', 'i', 'G', 'l', 'j', '5467', '9219', 'j', 'q', 'n', '5465', '6197', 'J', 'y']

SOLUTION: 30507

PROBLEM: ['4145', 't']

SOLUTION: 4145

PROBLEM: ['C', 'u', 'y', '9609', 'M', 'k']

SOLUTION:
9609