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: ['w', '491', 'x', 'u', 'z', 'q', '5411', '7629', '8261', '8629', '1441', '5139', 's', 'm', '6463', 'u', 'z']

Answer: m, q, s, u, w, x, z


Question: ['4343', 'r', '499', 'u', '2537', '1723', '2851', 'l', '5209', '4061', '2901', 'e', 'f', 'f', '9357', '4201', '4939', 'g', '1613', '3403', 't', '4501', '1847', 'o', 'e', 'z']

Answer:
e, f, g, l, o, r, t, u, z