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: ['O', 'j', 'Z', 'u', '7427', '4225', '3139', '9993', '9945', '3639', 'h', 'j', 'f', '6511', 'e', '4607', '2741', '4743']

SOLUTION: 56970

PROBLEM: ['5331', 'f', '2865', '6019', 'U', 'm', 'g', 'n', 'Y', 'A']

SOLUTION: 14215

PROBLEM: ['n', 'J', '4743', '7737', 'f', 'S', '931', '3849', 'I', 'Q', '3571', '9367']

SOLUTION:
30198