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: ['507', 'P', '9697', 'u', '5057']

SOLUTION: 15261

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

SOLUTION: 56407

PROBLEM: ['7629', 'j', 'r', '7493', '2223', '4887', '8363', 'b', '9737', '4885', 'z', '9917', 'b', '4907']

SOLUTION:
60041