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: ['2225', '1925']

SOLUTION: 4150

PROBLEM: ['4177', 'd', 'b', 'm', 'f', 'R', '797', '7905', '4355', '7515', '9801', 'F', 'R', '9125', '8445', 'k', 'K', 'K']

SOLUTION: 52120

PROBLEM: ['M', 'R', 'r', '6661', '517', '3539', '5665', 'd', 'r', '3965', 'j', '4735', '9325', '9297', '1661', '5751', '9013', '1483']

SOLUTION:
61612