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: ['8609', '8045', '2517', '3821', 'x', '3895', 't']

SOLUTION: 26887

PROBLEM: ['r', '3537', 'T', '3611', 'k', '4983', 'h', '4317', '8727', 'E', '6471', '8465', 'f', '5429', 'T', '2169', '2171', 'P', '6941', 'D']

SOLUTION: 56821

PROBLEM: ['z', 'j', 'Z', '8161', '6927', 'w', '3803', '1205', '6633', '9921', 'u', 'a', 'u', '5683', '8421', '4643', 'B', '6155', '9671']

SOLUTION:
71223