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: ['2013', 'S', 's', '9353', 'b', 'u', '6687', '5429', '3545', '7269']

SOLUTION: 34296

PROBLEM: ['3705', '9217', 'C', '4609']

SOLUTION: 17531

PROBLEM: ['g', 'A', 'r', '539', '5459', '2725', '7447', '3693', '1757', 'r', 'W', '5949', '4569', '5153', '3985', 'Q', '505', 'M', '8989']

SOLUTION:
50770