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: ['9403', 'u', '4159', 'w', '3467']

Answer: 17029


Question: ['j', 'f', '3831', 'B', 'D']

Answer: 3831


Question: ['2167', '2309', '4179']

Answer:
8655