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: ['4299', 'b', '4171', '7639', '6609', '927', '5249', 'o', 'p', '9851', 'e', '1311', '3777', '7799', '7687', '8809', 'c', 'r', '47', '1925', '1847', 'r', 'd', 'r', '1871', '5935', 'r', '2283', 'p', 'p', '2727', 'c', 'i', '7357', 'y', '5103', '6115', 'q', 'w', 'u', '9201', '4221', '7717', 'o']

Answer: b, c, d, e, i, o, p, q, r, u, w, 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: ['e', 'u', 'p', 'a', 'r', 'y', '1081', '8329', 'm', 'y', 'g', '2921', '5091', '7541', '6711', 'i', 'n', '1149', 'w', 't', '97', '1693', 'x', 'y', 'j', 'k', '8073', '1575', 'w', '1649']

Answer:
a, e, g, i, j, k, m, n, p, r, t, u, w, x, y