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: ['u', '1805', 'l', 'l', '5449', 'r', '4471', 'a', 'u', 'c', 'q', '6463', '6717', '7025', '9359', 'q', 'h', '1989', '5497', 'h', 'd', 'c', '135', '5737', '1235', 'v', 'u', 'g', 'p', 't', '9223', '8289', '4489', 'n']

Answer: a, c, d, g, h, l, n, p, q, r, t, u, v


Question: ['v', 'l', 'v', '7673', '8975', 'u', '2471', '4151', '3615', '1139', 'i', 'z', '8833', 'v', '341', 'l', 'n', 'l', 'd', '9207', '1861', '3901', 'a']

Answer: a, d, i, l, n, u, v, z


Question: ['6081', 'l', '3023', '6549', '7577', 'a', 'f', '9903', '8661', 'o', 'v', '8967', 'm', 'e', 'n', '1425', '8153', 'g', 'i', '8359']

Answer:
a, e, f, g, i, l, m, n, o, v