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: ['p', 'k', 'i', '753', 'u', 'm', '3817', '1597', 'l', 'm', 'a', 'i', 'b', 's', 'c', '2561', 'x', '5363', '1173', '8657', '2033', 'b', 'p', '3093', 'k', '6535', '307', '9925', 'b', 'q', 'q']

Answer: a, b, c, i, k, l, m, p, q, s, u, x


Question: ['i', '1129', 'f']

Answer: f, i


Question: ['7139', '4679', 'r', '9741', 'j', '8105', 't', 'v']

Answer:
j, r, t, v