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: ['5573', '6221', 'C', '8649', '6603', 'q', '9403']

SOLUTION: 36449

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

SOLUTION: 30507

PROBLEM: ['5715', 'r', 'R']

SOLUTION:
5715