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: ['r', '3537', 'T', '3611', 'k', '4983', 'h', '4317', '8727', 'E', '6471', '8465', 'f', '5429', 'T', '2169', '2171', 'P', '6941', 'D']

SOLUTION: 56821

PROBLEM: ['r', '2251', 'X', 'H', 'a', '5463', 'g', 'M', '9797', '1581', 'o', 'm', 'v', 'E']

SOLUTION: 19092

PROBLEM: ['3243', 'W', '5799', 'T', 'y', 'D', '2543', '911', '3665', '753', '5701', '1471', 'o']

SOLUTION:
24086