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: ['N', 'V', 't', 'X', 't', 'M']

Answer: 0


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

Answer: 17029


Question: ['3391', 'f', '4897', '3969']

Answer:
12257