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: ['5163', 'n', 'j', '67', '3801', 'n', '7113', 'z', '579', '6885', '8921', 'v', '5481', '5507', 'k', '8403', 'c', '837', 'u', '6341', 'd', 'i', '497']

Answer: c, d, i, j, k, n, u, v, z


Question: ['s', '2059', 'y', 'k', 't', 'q', '4575', 'p', 'd', '7969', 'w', '1305', 'd', '1981', 'o', '2537', '1395', '3865', '8319', 'c', '7189', '7033', 'o', 'd', 'o', 'z', '2233', 'i', 'l', 'f', 'b', 'j', 'v', 'f', 'v', '5651', '4927', '2403', '7053', '6135', '3655', 'r', 's']

Answer:
b, c, d, f, i, j, k, l, o, p, q, r, s, t, v, w, y, z