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: ['w', '8777', 'y', 'e', '8015', 't', 'w', '53', '9149', 'e', 'k', '1837', 'b', 's', '4007', '4905']

Answer: b, e, k, s, t, w, y


Question: ['z', '8763', '6399', '45', '6731', 'v', '441', '4763', 'u', '8741', 'r', '9143', 'd', 'p', '2241', 'y', '6523', 'y', 'w', '6771', 't', 'r', '9239', '295', 'z', '461', 'b', '9217', '2597', '1249', 'r', 'i']

Answer: b, d, i, p, r, t, u, v, w, y, z


Question: ['t', '8019', 's', 'v', 'u', 'm', '1783', '8009', '6045', '3587', 'a', 'h', 'e', 't', '1879', 'u', '9235', 'j', 'p', '5853', 's', '2087', '4107', 'b', 'z', '1365', 'x', '9923', 'e', '815', 'e', '6745', '1803', 'u', '9323', 'o', '5347', '7963']

Answer:
a, b, e, h, j, m, o, p, s, t, u, v, x, z