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: ['1391', '1719', '8547', 'x', 'a', 'j', '6395', 't', '3421', '6607', 'M', '1645', 'H', 'x', 't']

SOLUTION: 29725

PROBLEM: ['7087', 'P', 'i', 'e', '4875', 'e', 'F']

SOLUTION: 11962

PROBLEM: ['5185', '2919', '7361', '9837', '4509', '6769', 'a', '1987']

SOLUTION:
38567