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.

Ex Input:
['6921', 'a', 'U', '2821', '2111', 'h', '3937', '3697', 'd', '6309', 'q', '7961', '5287', '5375', '2721', '4523', 'V', '8633', 'c', '7643']

Ex Output:
67939


Ex Input:
['2787', 'z', '9351', '3339']

Ex Output:
15477


Ex Input:
['5845', '7621', 'z', '7607', '161', '9015', 'M', '5067', 'q', '7117', '5003', 'r', '6057', '3851']

Ex Output:

57344