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: ['6577', 'Q', '6865', '7671', 'N']

SOLUTION: 21113

PROBLEM: ['o', 'O', 'H', '7619', '6435', 'X', 'g', '1663']

SOLUTION: 15717

PROBLEM: ['313', '8229']

SOLUTION:
8542