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: ['o', 'a', 'K', '6031']

SOLUTION: 6031

PROBLEM: ['X', 'P', 'x', '9471', '5', 'c', 'f', '5077', '1085', '2267', 'R', 'q', '4987', '9529', 'H', 'n', 'r', 'u']

SOLUTION: 32421

PROBLEM: ['7769', 'N', '2505', '8997', 'I', '2547', '3399']

SOLUTION:
25217