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: ['u', '9249', 'u', 't', 'm', 'm', 'n', 'w', '8617', '2729', 'i', 'l', '2971', '3227', 'b', '9017', '4711', 'i', 't', 'r', 'a', 'a', '1701', '6397', '4535', '9167', '6039', '6111', '849', 'p', '8197', '2645', '5147', 'u', 'l', '7419', 'w', 'w', 'k', 'x', 'c', '3377', '4015', '1297', 'f']

Answer: a, b, c, f, i, k, l, m, n, p, r, t, u, w, x


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: ['w', 'k', '6723', '3999', 'q', 'v', 't', '2995', '6731', '2269', 'k', '4021', 'u', '3133', '8253', '6525', 'z', 'f', 'u', '1061', 'd', '7803', 'g', 's', '9741', '5111', '731', '399', 'e', '9613', '5237', 'x', 'm']

Answer:
d, e, f, g, k, m, q, s, t, u, v, w, x, z