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: ['j', '8797', 'i', '5443', 'i', 'f', '7593', 'u', 'h', '3251', 'l', '681', 'y', 'n', 'r', '1699', '1379', '8987', '6955', 'x', 'p', 'x', '553', 'q', '5679', 'q', 'w', '9007', 'r', '8945', '7351', 'a', 'v', 'k', '1309', 'v', 'i', '4161', 'a', 'q', '2919', '6917', '6845']

Answer: a, f, h, i, j, k, l, n, p, q, r, u, v, w, x, y


Question: ['4009', 'y', '9077', 'p', 'q', '6711', '6443', '5491']

Answer: p, q, y


Question: ['4931', '1643', '8845', 'z', 'e', '7307', '4945', 'g', 's', 'd', '2117', '3795', '7975', '8599', '8627', '8783', 'b', 'j', 'o', '2247', 'g', 'd', 'l', 'p', 'y', 'o', 'y', 'a', 'f', 'i', '3789', '4693', 'g', 'f', 'v', '6235', '169', '7825', 'l', 'u']

Answer:
a, b, d, e, f, g, i, j, l, o, p, s, u, v, y, z