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: ['2521', '8027', 'm', '193', '615', 'l', '1947', '5949', '6307', 'r', '1015', '743', 'v', '6949', 'b', 'g', '8841', 'c', 'b', '2879']

Answer: b, c, g, l, m, r, v


Question: ['d', 'g', '9019', '9987', '8713', '9513', 'a', '2043', 'd', '5817', 'w', 'd']

Answer: a, d, g, w


Question: ['f', 'u', 'q', '8565', 'h', '9883', 'f', 'e', 'i', '9929', 'k', 'j', '7449', '3761', '1675', 'v', 'p', '4625', '3167', 'u', '5799', 'b', 't', 'p', 'k', '1339', '8549', 'q', '6083', '1235', '3597', '2651', '3045', '5343', '5511', 'c', '61', '4977', '9557', '5605', 'o', '8593']

Answer:
b, c, e, f, h, i, j, k, o, p, q, t, u, v