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: ['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: ['205', '7909', 'y', 'q', '2141', '1873', 'o', '7675', '8593', 'v', 'g', 'e', '3607', 'a', 'k', '7599', '7247', '7427', 'a', '425', '4737', 'z', 'm', 'r', 'a', 'o', '3537', 'x', 'q']

Answer:
a, e, g, k, m, o, q, r, v, x, y, z