instruction:
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.
question:
['6921', 'a', 'U', '2821', '2111', 'h', '3937', '3697', 'd', '6309', 'q', '7961', '5287', '5375', '2721', '4523', 'V', '8633', 'c', '7643']
answer:
67939


question:
['6469', '3027', 'Z', '3353', 'a', 'S', '3879', '8471', 'H', 'I', 'y', '2661', '9007', 'D']
answer:
36867


question:
['r', 's', 'D', '1375', 'w', 't', 'P', 'r']
answer:

1375