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: ['1189', '7143', '993', '1513', '6449', '9749', '5963', '8159', 't', '3543', 'j', 'i', '4227', '1463', '6431', '4987', 'y', 'q', 'f', '321', 'm', 'r']

Answer: f, i, j, m, q, r, t, y


Question: ['4787', 'c', '1727', '9863', '8147', '3931', 'b', '1133', '3023', '7427', '7837', 'n', '7921', 'o', 'c', '3973', '1949', 'x', 'g', 'b', 'd', '8559', '8661', '4465', 'z', '369', 'q', 'e', 'y', '8629', '7665', 'i', 'r', 'n', 'z', '9115', '1393', '4899']

Answer: b, c, d, e, g, i, n, o, q, r, x, y, z


Question: ['479', '5337', '8705', '1849', 'a', 'l', 'n', '1901', 'w', 'n', 'd', '6311', '7363', 'o', '105', 'z', 'e', 'p', '6723', '6821', '4467', '4109', '6145', '427', '6479', '283', 'y', 'm', '7507', 'e', 'w', '1419', '5389', 'g', '6653', '1859', '5493', 'k', '8385', 'u', 'e', '4079']

Answer:
a, d, e, g, k, l, m, n, o, p, u, w, y, z