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: ['n', 't', '2901', '9697', 'a', 'j', 'x', 'a', '4437', '2255', '2177', 's', '3173', 'j', 't', '5713', '4091', '4253', '5553', 'i', '4533', 'i', 'e', '6899', 's', '3541', '2139', '2705', 'm', 'u']

Answer: a, e, i, j, m, n, s, t, u, x


Question: ['6175', '9441', '7127', '5979', 's', '1367', 'e', 'm', '7083', '1787', '8375', '2851', '3475', 'r', '697', 'g', 'z', 'm', '4207', 'c', '7971', 'z', '9339', 'd', 's', '3507', '9003', 'i', 'y', 'w', 'j', 'i']

Answer: c, d, e, g, i, j, m, r, s, w, y, z


Question: ['d', '3329', '4385', '3841', 'g', '9455', '3529', '265', '9179', '6913', 'v', '6201', 'b', '4087', 't', 'u', 'm', '8201', 'y', 'a', '9133', 'c']

Answer:
a, b, c, d, g, m, t, u, v, y