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: ['4437', '1265', '1519', 'K', 'Q', 'b', 'n', 'J', '6631', 'K', 'q', 'D', 'U', 'u', '3653', '5169', 'L', 's']

SOLUTION: 22674

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

SOLUTION: 43470

PROBLEM: ['3947', '8289', 'E', '7953', '6043', '1959', '8747']

SOLUTION:
36938