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: ['e', 'n', 'y', 'f', 'l', 'h', '455', 'y', '591', 'm', '9041', 'b', 'b', 'o', '4215', '5009', 'o', 'a', '4369', 'u', '6911', '4825', 't', 'k', '6063', '2939']

Answer: a, b, e, f, h, k, l, m, n, o, t, u, y


Question: ['y', '2305', '5671', 'q', '1027', '9593', '3381', '3017', 'x', '8745', '8005', 'f', 'y', 'n', '787', '4617', 'a', '5903', '2021', '4021', 'q', '1343', 'o', '9247', 'f', '3725', '7207', 'e']

Answer:
a, e, f, n, o, q, x, y