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: ['a', '7599', 'i', '9455', '3955', '2015', 'j', '7345', 'x', 't', 'c', '1317', '9155', '6383', '7793', 'n', '5581', 'v', '3485', 'n', 'r']

Answer: a, c, i, j, n, r, t, v, x


Question: ['f', '6817', 'f', 'd', '3835', '3051', 'u', 'l', '7679', 'b', '3931', '1441', 'q', '8675', 's', '5487', 'y', '2279', 'x', 'y', '9513', '2875', '1771', '879', '2927', '3469', 'v', 't', 'k', '9991', '2565', '7345', '973', 'w', 'i', '6105']

Answer: b, d, f, i, k, l, q, s, t, u, v, w, x, y


Question: ['1651', '1447', '3401', 'y', '3665', '5589', '6331', 'j', '361', '4111', '2485', '8051', 'n', 'o', '4715', '3097', '795', '5279', '4145', '4403', '2077', '865', 'o', 'c', '3355', '7041', 'e', '9017', 'v', '4843', '3443', 'o', 't', 'b', 'g', 'h', 'y', 'o', 'f']

Answer:
b, c, e, f, g, h, j, n, o, t, v, y