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: ['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: ['c', '1693', 'l', 'u', 'x', '3609', 'h', '4159']

Answer: c, h, l, u, x


Question: ['9265', '1311', 'o', 'a', 'v', 'w', '1437', '5201', 'g', '6411', '6277', 'i']

Answer:
a, g, i, o, v, w