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: ['q', '6421', 'w', 'x', '669', 'h', '3853', '6609', 'p', '947', 'g', 'c', 'x', '2617', 'v', 'e', '4795', '5755', 'a', '2379', 'y', '5939', 'l', 'h', 'g', '3779', 'c', 'm', '3157', '4027', 'g', '2917', '9461', '7271', 't', 'i', '9807', '147']

Answer: a, c, e, g, h, i, l, m, p, q, t, v, w, x, y


Question: ['3583', 'd', '1481', 'w', 'l', '7261', '2933', 'n', '8725', 'g', '3441', 'r', '287', '7327', '5637', 'r', '5389', 'm', 'j', 'd', 'a', 'e', 'v', '7879', '1731', 'z', '43', 'q', 'p', '4315', 'p', '3651', 'o', 'l', 's', '9787', 'h', '6735']

Answer: a, d, e, g, h, j, l, m, n, o, p, q, r, s, v, w, z


Question: ['7171', '2457', '2605', 'z', 'y', 'r', 'i', 's', '8795', '2165', 'z', 'v', '3429', '4075', '4677', '6557', 'p', '6873']

Answer:
i, p, r, s, v, y, z