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: ['887', '8133', 'X', '2253', '8461', 'I', '5425', 'Z', 'z', 'r']

SOLUTION: 25159

PROBLEM: ['9445', '7291', 'r', 'g', '1175', '7823', '5507', 'j', '7249', '6335', '3853', 'b', 'u', 'S', '365', 'Z', '7489', 'S', 'W', 'e']

SOLUTION: 56532

PROBLEM: ['Y', '2471', '4373', 'u', '7161', '1055', 'n']

SOLUTION:
15060