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: ['k', '1489', 'x', '6543', 'I', 'l', 'D', '6299', '1473', 'a', '7661', 'z', 'E', 'Z', 'U', '3671', '2873', 'e', 'p']

SOLUTION: 30009

PROBLEM: ['f', '6703', 'c', 'c', 'l', '2511', '6507', 'b', '9727', 'l', '1251', 'I', '5231', '91', 'L', 'M', 'd']

SOLUTION: 32021

PROBLEM: ['n', 's', 'X', 'B', '8391', 'P', 'b', 't', 'L', '3675', '4419', 'I', 'b', '1257']

SOLUTION:
17742