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: ['8829', 'm', '5369', 'q', '5737', '7799', '5705', 'p', 'w', '1983', '4849', 'h', '6771', 'p', 'y', '1071', 'u', '6401', '7723', 'p']

Answer: h, m, p, q, u, w, y


Question: ['u', '635', '5249', '9457', 's', '9317', '9407', 'l', 'w', '9705', 'k', '429', '5489', 'e', 'd', '2457', 'o', '4665', '1675', 'l', 'y', 's', 'o', 't', '4285']

Answer: d, e, k, l, o, s, t, u, w, y


Question: ['8719', '7495', '6515', 'k', '5909', '5137', 't', 'y', '6943', '1387', '6971', '8161', 'v', 'd', '5733', '8959', 'x', 'm', 'x', '1375', '9125', 'd', '1169', 'y', 'x', 'o', 'm', '9663', 'a', 'd', '9099', '5691', 't', '8975']

Answer:
a, d, k, m, o, t, v, x, y