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: ['g', 'A', 'm', '4005', '8079', 'G']

SOLUTION: 12084

PROBLEM: ['B', 's']

SOLUTION: 0

PROBLEM: ['7809', 'C']

SOLUTION:
7809