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: ['4425', 'x', '1959', 'C', 'c', 'D', 'M', '8317', 'q', 'x', '4277', 'N', 'z', 'I', '1921', 'o', 't']

SOLUTION: 20899

PROBLEM: ['c', 'd']

SOLUTION: 0

PROBLEM: ['w', 'I', 'Q', 'j', 'B', 'e', 'l', 'S', '9457', '1717', 'V', '6443', '4895', 'g', '3329', '8993']

SOLUTION:
34834