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: ['7013', '8755', 'u', '9377', 'n', '6997', '507', '8557', '9745', 'g', '3019', '93', 'l', '1219', 'a', '393', '2573', 'q', 'b', '6101', 'e']

Answer: a, b, e, g, l, n, q, u


Question: ['1931', 'c', 's', '8767', 'z', '8977', '9249', '365', 'p', '7187', 'p', '961', 'k', 'k', '423', '5999', '4697', '6251', '6441', '1821', 's', 's', 'f', '5365', 'z', '5113', 'y', 'k', 'i', '5627', 'u', 'w', '4103', '8035', '7105', 'o', 'n', 's', 'y']

Answer: c, f, i, k, n, o, p, s, u, w, y, z


Question: ['9667', 'z', 'x', 'f', '759', 'a', '7825', '1253', 'r', '5593', 'u', '2219', 'w', '2563', 't', '9809', '5263', '9773', 'w', '6337']

Answer:
a, f, r, t, u, w, x, z