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: ['w', '743', '5757', '8731', 'k', 'p', '317', 'n', 'x', '5649', 'l', 'm', 'c', '2499', 'l']

Answer: c, k, l, m, n, p, w, x


Question: ['163', 'x', 'g', '5997', 'm', 'l', '7225', '7907', '375', 'y', 'a', 'j', 'c', 'j', '7755', '147', 'h', '3845', 'y', 's', 'h', 'u', '8737', '6091', 'j', 'f', 'c', '7395', '881', '1771', 'y', '3691', 'h']

Answer: a, c, f, g, h, j, l, m, s, u, x, y


Question: ['z', 'c', '7313', 'n', '7757', '4395', 'j', 'c', 'w', 'i', 'q', '5', 'u', '5277', 'e', 'j', '5353', 'k', 'u', '6679', '4145', '9109', 's', 'x', 's', 'f', 'y', 'w', 'z']

Answer:
c, e, f, i, j, k, n, q, s, u, w, x, y, z