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: ['315', '9975', '3013', 's', '6131', 'e', 'e', 'u', 'a', '1729', 'g', 't', 'y', 'f', '7523', 'e', 'g', '489', 'm', 'p', 'f', 'e', '2077', 'e', 'g', 'c', 'l', '6389', 'k', 'b']

Answer: a, b, c, e, f, g, k, l, m, p, s, t, u, y


Question: ['g', '6867', '7965', '3313', 'k', '1827', '7337', 'u', '1209', '5145', 'w', 'h', '9059', 'u', 'b', '3189', '2837', 'k', 'y', 'e', 'b', '4479', '541', '7103', 'h', 'm', '2177', '6377', '3993', '7167', 'q', '2145', '5007', '9135', '5331', 'e']

Answer: b, e, g, h, k, m, q, u, w, y


Question: ['e', '5681', 'd', 'w', '4127', '511', 't', 'h', '421', 'r', '8167', 'w', '2721', '5069', 'x', '7789']

Answer:
d, e, h, r, t, w, x