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.
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Question: ['4389', '8535', 'D', '6063', 'z', 'r', 'w', '5725', '291', 'a', '9059', '569', '2943', 'W']

Answer: 37574


Question: ['A', '771', 'Q', 'b', '9929', '4991', 'q', '9863', '4363', '5721', 'C', '991', 'j', 'r', 'Q', 'B', 'K']

Answer: 36629


Question: ['u', 'I', '5971', 'z', '3957', 'K', '8193']

Answer:
18121