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: ['K', 'O', 'p', '1669', '8647', '3417', 'a', '8903', 'V', 'E', 'l', 'a', '5177', 'J', '6559', '5377', 'X', '9427']

SOLUTION: 49176

PROBLEM: ['U', '5885', 'u', 'Y', 's', 'w', 'j', '9629', '9505', 'U']

SOLUTION: 25019

PROBLEM: ['O', '1713', '9687', '8983', '1273']

SOLUTION:
21656