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: ['9403', 'u', '4159', 'w', '3467']

SOLUTION: 17029

PROBLEM: ['4389', '8535', 'D', '6063', 'z', 'r', 'w', '5725', '291', 'a', '9059', '569', '2943', 'W']

SOLUTION: 37574

PROBLEM: ['v', '5235', '2735', '2483', '6201', '2609']

SOLUTION:
19263