In this task, you are given an input list A comprising of numbers and alphabets. You need to extract and sort the unique alphabets in the list. The alphabets in the input list will only be in lowercase. Return -1 if there is no alphabet in the input list.
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Question: ['4213', '3595', '7937', 'y', '5723', 'v', 'b', '7007']

Answer: b, v, y


Question: ['2181', '7019', 'l', 'z', 'z', 'y', '1245', '4179', '6951', '7249', '2723']

Answer: l, y, z


Question: ['y', 'g', 'r', 'z', '4167']

Answer:
g, r, y, z