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: ['w', '1367', '5389', '9515']

Answer: w


Question: ['w', '5341', 'b', '6243', 'v', '877', '1087', '6763', '5241', '3369', '9119', 't', 'v', 'j', '8261', 'o', 'b']

Answer: b, j, o, t, v, w


Question: ['1361', '6067', 'r', '53', 't', '517', 'n', '8481', '2029', '2795', '9543', 'j', 'p', 'n', '5449', '2679', 'q', 'e', 'v', 'h', '8059', '8351', 'q', '1599', 'l', '3677', '4425', '6331', '9585', 'm', '7805', 'e', '8491', 'l', '3481', '6769', '1777', 'l']

Answer:
e, h, j, l, m, n, p, q, r, t, v