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: ['h', 'g', '4563', 'v', 'm', '107']

Answer: g, h, m, v


Question: ['r', 's', '2471', 'n', '635', 'k', '3551', '7041', '8765', '1221', '8439', '7773', '6471', 'u', 'p', '2093', '6479', '1435', '6881', 'a', 'y', 'm', 'r', '1627', 'w', 'k', 'b', '3095', '9059', '285', 'y', 'a', 'm', 'x', '637', 'i', '3407', 'e', 'e']

Answer: a, b, e, i, k, m, n, p, r, s, u, w, x, y


Question: ['5465', '7029', 'n', 'f', '7451', 'w', '1023', 'w', 'x', '507', 'f', 'z', '4127', '3113', '7209', 'c', 'h', '1115', '599', 'f', '3383', 'h', 'c', 'a', 'h', '1027', '6531', '9133', '9061', 'b', '2711', 'i', 'a', '5239', '1431', 'r', '4561']

Answer:
a, b, c, f, h, i, n, r, w, x, z