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: ['2697', 's', '8733', 'n', '5871', 'f']

Answer: f, n, s


Question: ['1641', 'q', 'q', 'p', 'o', '5031', '6829', '9579', 'c', 's', '8993', 'j', '3385', '9149', 't', '1893', 'u', '4195', '555', 's', '5147', '2473', '6153', 'p', 'z', 'c', '2017', '9391', 'j', '7161', '4687', 'i', 'b', 'g']

Answer:
b, c, g, i, j, o, p, q, s, t, u, z