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: ['n', 'G', '5059', '8343', '8673', 'P', 'N', '5485', '2279', '6121', 'i', 'U', '7277', '8701', 'A', 'b', 'Z', 'R', '6371', 'G']

SOLUTION: 58309

PROBLEM: ['r', 'b', 'G', 'H', '255', '6809', '5133', '1059', '4317', 'P', '7219', 'd', '805', 'G', '5243', '8305', '8509', 'o']

SOLUTION: 47654

PROBLEM: ['3841', '3155', 'j', 't', 'T', 'd', '3597', '4931', 'B', 'n', '8361', '7775', 'k', 'E']

SOLUTION:
31660