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: ['6469', '3027', 'Z', '3353', 'a', 'S', '3879', '8471', 'H', 'I', 'y', '2661', '9007', 'D']

SOLUTION: 36867

PROBLEM: ['6321', 'M', 'd', '3673']

SOLUTION: 9994

PROBLEM: ['3859', '1389', 'q', '7659', '8745', 'D', '2907', '5767', 'N', '8565', 'N', 'R', 'S', 'Y', 'P', '8057', 'a']

SOLUTION:
46948