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: ['Y', 'X']

SOLUTION: 0

PROBLEM: ['7187', '5651', 'd', '4869', 'q', '2375', '3547']

SOLUTION: 23629

PROBLEM: ['q', '867', 'e', 'z']

SOLUTION:
867