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: ['887', 'p', '3819', '2727', '1407', 'b', 'n', '737', 'd', 'w', 'q', '6877']

Answer: b, d, n, p, q, w


Question: ['1749', 'i', 'w', 'j', '3171', '1999', '1037', '4937', '7013', '3593', '287', 'o', 'i', 'j']

Answer: i, j, o, w


Question: ['9409', '5577', 'j', '695', 'm', '7073', '3037', 'r', '8209', 'd', 'i', 'k', '6549', 'p', 'w', '9409', '8887', '5605', '4279', '8989', '6003', '8899', '247', 'd', '1427', 'y', '9115', 't', '8625']

Answer:
d, i, j, k, m, p, r, t, w, y