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: ['z', 'U', '6817', 's', '3731', 'M', 'I', '1095', 'l', '5993', '5207', 'e', 'L', '5361', 'v', 'g', '1963', '4829', '9541', '8261']

SOLUTION: 52798

PROBLEM: ['f', '6703', 'c', 'c', 'l', '2511', '6507', 'b', '9727', 'l', '1251', 'I', '5231', '91', 'L', 'M', 'd']

SOLUTION: 32021

PROBLEM: ['1399', '4683', 'I']

SOLUTION:
6082