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: ['o', 'l', 'm', 't', '4487', '1019', '9903', 'c']

Answer: c, l, m, o, t


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: ['f', 'h', '1731', 's', '8855', '6971', 'n', '4637', 'o', '3423', 'i', 'n', 's', '65', 'e', '3843', 'a', 'h', 'p', '9919', 'i', 's', '4259', '3319', '1303', '9257', 'w', '6607', 'r']

Answer:
a, e, f, h, i, n, o, p, r, s, w