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: ['1595', '2915', 'o', 't', 'c', 'h', '3969', '5407']

Answer: c, h, o, t


Question: ['231', 'r', '5673', 'j', '589', 'z', '4659', 'a', '3763']

Answer: a, j, r, z


Question: ['2505', '4199', 'e', '5433', '8795', 'q', 'i', '9357', 'o', '257', '8235', 'b', '1339', 'w', '1463', 'm', '277', '3211', '3863', 'r', 'm', 'i', '5793', '7451', '4787', '4739', 'k', 't', 'o', '7453', '9385', 'v', 'l', 'y', 'f', 'r', 'p', 'w']

Answer:
b, e, f, i, k, l, m, o, p, q, r, t, v, w, y