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: ['8315', 'b', '4333', 'f', '6507', '6211', '3475', 'c', 'e', '8039', '661']

Answer: b, c, e, f


Question: ['y', 'p', 'q', '2157', 'b', 'w', '8875', 'k', 'i', 'd', '9743', '4941', 'b', 'p', '9941', '495', 'h', 'i', '839', 'c', 'h', 'f', 'b', 'a', 'k', 'z', '7549', '4149', 'h', 'j', '1947', 't', 'f', 'c', '1243']

Answer: a, b, c, d, f, h, i, j, k, p, q, t, w, y, z


Question: ['w', 'h', 'k', 's', '4937', 'q', '2409', 'y', '7699', 'z', 's', '9113', 'k', '335', '707', 'w', '3635', '3097', '9821', 's', 'h', '7757', '9867']

Answer:
h, k, q, s, w, y, z