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: ['7965', '6465', 'c', '7963', 'j', '6839', '9989', '1019', 'x', '1303', '2633', 'y', '6865', 'a', 'k', '635', '3719', '7229', 'k', 't', 'r', '5741', '9569', '4931', '1125', 'f', '5429', 'c', '2065', '6315', 'e', '6877', '2005', 'x', '7831', '7297', 'm', '3571', 'b', '8617', '2981', 'i', '5105', 'g', 'u']

Answer: a, b, c, e, f, g, i, j, k, m, r, t, u, x, y


Question: ['1367', 'h', '4153', '1587', 'h', 'b', 'n', 'u', 'n']

Answer: b, h, n, u


Question: ['8661', '9187', '5651', '8985', '5495', 'e', '1327', 'a', 'n', '8187', 'w', 'y', '91', '9623', '7099', '7145', '9227', 'b', 'o', 'j', '8369', '1901', '815', '3647', 'x']

Answer:
a, b, e, j, n, o, w, x, y