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: ['Q', '8317', '8989']

SOLUTION: 17306

PROBLEM: ['D', 'K', 'n', 'd', 'i', 'U']

SOLUTION: 0

PROBLEM: ['X', '43', '2151', 'v', '5385', 'l', 'B', '6611', '9063', '621', '7379', 'P', 'C', '1503', 'e', 'D', 'u', '4861', '9987', '6015']

SOLUTION:
53619