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: ['o', '1099', 'r', '8995', 'o', '2909']

Answer: o, r


Question: ['6769', '1057', '1021', 'n', '8231', '9173', '8123', 'a', '6053', 'q', 'y', '883', 'r', '1215', 'x', 'o', '9531']

Answer: a, n, o, q, r, x, y


Question: ['e', 'm', 'o', '9445', 'm', 'l', '5655', 'e', 'z', '9115', '7899', 'k', 'h', 's', 'm', '3101', 'o', '5087', 'h', '6327', '5983', 'p', '8389', '93', '7861', 'o', 'k', 'x', '7153', 'e', '8295', 'l', '4169', 'b', 'y', 'l', 'h', '7715']

Answer:
b, e, h, k, l, m, o, p, s, x, y, z