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: ['653', '1969', '6235', '6283', 'd', 'e', '465', 'e']

Answer: d, e


Question: ['3113', '3311', '1759', 'x', 'm', '5335', '6325', 'u', 'n', '6441', '9931', '9219', 'y', '7647', '8241', 'r', '2681', '9827', 'f', 'y', 'f', 'z', 'p']

Answer:
f, m, n, p, r, u, x, y, z