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: ['C', '9973', 'b', '693', 'y', 'H', 'C', 'P', 'b', 'J', 'f', 'T', '2317', 'O', '5755', '8201', 'p', 'y', '8721', 'i']

SOLUTION: 35660

PROBLEM: ['S', '1249', '6233', 'I', '6733', 'r', 'A', 'E', 'h', 'x', 'p', 'c', '515', '1029', '1593', '1035']

SOLUTION: 18387

PROBLEM: ['K', 'D', '9175', '6701', '6547', 'T', '7815', 'n', '8953', '2051', '6675', 'V', '4871', 'X', 'l', 't', 't', '9617', '3313']

SOLUTION:
65718