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: ['v', '2989', 'z', '7843', 'e', '9923', 'y', 'b', '7611', 'u', 'u', '6227', '3145', 'w', '6451', 'g', '3129', 'o', 'r', 'z', '8349', 'u', 'h', 'd', 'g', 'a']

Answer: a, b, d, e, g, h, o, r, u, v, w, y, z


Question: ['5973', 'h', '4081', 'i', '8059', 'w', 'j', '6175', 'w', '8685', '5811', 'k', 'n', '5577', '9817', 'v', '8617', 'u', 'y', '3921', 'b', '1027', '5405', 'a', '3501', '6659', 's', 'e', '157']

Answer: a, b, e, h, i, j, k, n, s, u, v, w, y


Question: ['2857', '5705', 'v', '6285', 'q', '4251', 'p', 'h', 'k', 'g', 'd', 'b', 'i', '6845', 'o', 'c', 'z', '3011', '9705', '6303', 'k', 'z', 'u', '3979', 'r', 'z', 'n', 'z']

Answer:
b, c, d, g, h, i, k, n, o, p, q, r, u, v, z