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: ['3809', '9401', '63', '5705', 'u', '6275', 'k', 'l', '1171', '9365', 'L', 'O', '7431', '8567', 'h', '6135']

SOLUTION: 57922

PROBLEM: ['B', 'u', '9227', 'b', '8767']

SOLUTION: 17994

PROBLEM: ['Z', '9943', 'X', '9015', 'M', '5103', 'N', 'x', 'n']

SOLUTION:
24061