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: ['1595', '2915', 'o', 't', 'c', 'h', '3969', '5407']

Answer: c, h, o, t


Question: ['z', '3219', '6399', '2357', '7597', '357', 'k', 'k', 'u', 'd', '6115', 'w', '2921', '8809']

Answer: d, k, u, w, z


Question: ['6601', '5449', 'j', '7389', 'y', '6011', '1107', 'q', 'u', 'z', 'c', '1563', '689', '3793', 's', 'a', 'o', 'a', '4825', 'd', 'a', 'i', 'u', '5601', '543', 'z', '3505', 'w', '9729']

Answer:
a, c, d, i, j, o, q, s, u, w, y, z