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: ['1709', 'S', 'w', '7725', 'Z', '7755', '8081', '897', 'N', '4449', 'F', 'F', 'M', 'y', 'B', 'h', 's', 'l', 's', '415']

SOLUTION: 31031

PROBLEM: ['9989', 'B', 'E', '5181']

SOLUTION: 15170

PROBLEM: ['1689', 'h', '5391', 'f', '1929', '7411', 'k', 'C']

SOLUTION:
16420