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: ['3071', '355', 'e', '9781', 'R', '6833', 's', '2665', 'L', '9551', 'P', '6101', '2955', '4643', 'O', '3327', '2163', '685', '4277', 'B']

SOLUTION: 56407

PROBLEM: ['4601', '6021', '3005', 'I', 'f', '4631', 'Q', 'd', '8041', 'D', '8067', '7383', '757', 't', 'd', 'n', '2275', 'p', 'm', '6021']

SOLUTION: 50802

PROBLEM: ['4217', '9629', 'f', 't', 'Q', '335', 'u', '6207']

SOLUTION:
20388