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: ['c', '8389', 'j', '6113', '5843', 'f']

Answer: c, f, j


Question: ['k', '8917', '3773', '6723', 'r', 'z', '3265', 'o', 'f', 'q', '9343', 'f', '1925', 'u', 'b', 'o', '5275', 'b', 'n', 'd', 'j', '4825']

Answer: b, d, f, j, k, n, o, q, r, u, z


Question: ['a', '2521', '3997', 'n', '3341', '8871', '1769', '5369', '7671']

Answer:
a, n