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: ['Q', 'v', 't', '223', 'm', 'l', 'c', 'M', 'b', '2227', 'P', 'e', 'n', 'f', 'S', '2205', '3517', '5545']

SOLUTION: 13717

PROBLEM: ['K', '479', 'u', '3489', 'o', '9589', '7153', '7649', '123', 'a', 'A', '3951', '847', 'N', 'R', '947', '9243', 'G', 'a']

SOLUTION: 43470

PROBLEM: ['3403', '7341', 'P', '7813', 'p', 'c', 'D', 'O', '3003', '4997']

SOLUTION:
26557