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', '1349', '3393', '7507', '2469', '8531', 'w', '6845', 'k', 'q', '2401', 'f', 'g', 'l', 'n', 'n', 'e', 'q', 'y', 'v', '3077', '4167', 'b', '5517', 'b']

Answer: b, e, f, g, k, l, n, q, v, w, y


Question: ['163', 'x', 'g', '5997', 'm', 'l', '7225', '7907', '375', 'y', 'a', 'j', 'c', 'j', '7755', '147', 'h', '3845', 'y', 's', 'h', 'u', '8737', '6091', 'j', 'f', 'c', '7395', '881', '1771', 'y', '3691', 'h']

Answer: a, c, f, g, h, j, l, m, s, u, x, y


Question: ['z', 'g', 'j', 'g', '8779', '6919', 'u', '4959', 'w', '511', 'k', 'z', '9109', '3945', '6391', '8663', '5695', '5027', 'b', 'z', '4619', 'f', 'y', '7113', 'i', 'r', '1857', '841', '5515', 'w', 'g', 'h', '9915', '8289', '2581', 'z', 'z']

Answer:
b, f, g, h, i, j, k, r, u, w, y, z