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: ['s', '6723', 'l', '1573', '1129', 'n', '4277', '5003', 'y', '7563', 'c', '6747', '3105', 's', '3593', '8417', '8253', '4157', 'w', 'f', 'z', 'd', '9685', '1033', 'h', '4893', 't', 'j', '6821', 'z', 'a', 'u', '591', 'o', '1087', '2147', '1223', '2339', 'i', 'y', '9307', 'x', 'z', 'r', 'y']

Answer: a, c, d, f, h, i, j, l, n, o, r, s, t, u, w, x, y, z


Question: ['7823', '2933', 'k', '4139', '5585', 'f', 'c', 'm', '2035', 'q', 'z', 'l', '1999', 'q', 'p', '7291', '2091', 'v', '423', 'e', 's', '6089', '4763', '6739']

Answer: c, e, f, k, l, m, p, q, s, v, z


Question: ['i', 'v', 's', 'c', 'n', 't', '8249', '8461', '5259', '7253', 'b', '2719', '9829', '4613', '8737', '907', '4027', '2399', 'm', '8657', 'l', 's', 'l', '9029', 'g', '2507', '8987', 'c', 'u']

Answer:
b, c, g, i, l, m, n, s, t, u, v