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: ['t', 'u', 'y', 'y', 'b', 'x', 'q', '3713', '2679']

Answer: b, q, t, u, x, y


Question: ['277', '8697', 'q', '2023', '5723', 'm', '8673', 'f', 'z', 'z', 'a', '9875', 'p', 'x', 'l', 'z', 'x', '619', '6509', 's', '2067', '571', 't']

Answer: a, f, l, m, p, q, s, t, x, z


Question: ['k', '8191', 'n', 'd', '9563', 'k', '1371']

Answer:
d, k, n