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: ['3723', 'v', 'j', 'e', '2017', 'd', '4211', '2079']

SOLUTION: 12030

PROBLEM: ['Y', 'X']

SOLUTION: 0

PROBLEM: ['s', 'M', 'U', '5383']

SOLUTION:
5383