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: ['7911', '7175', 'y', '9173', 'y', '2529', '831', 'k', '7197', 'j', '2343', 'i', 'b', '6799', '5987', '7277', 'n', 'x', 'h', '7209', 'l', 'd', 'm', 'e', '2277', '8909', 'x', '5361']

Answer: b, d, e, h, i, j, k, l, m, n, x, y


Question: ['895', '2049', '8839', '1773', 'v', '467']

Answer: v


Question: ['8823', 'x', '5913', '869', 'y', 'm', '9293']

Answer:
m, x, y