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: ['t', 'r', '2959', '2517', 'a', '9959', '729', '511', 'y', 'r', '465', 'c', '687', 'm', 'b', 'm', '3449', '9713', 'g', '8275', '8823', 'a', 'z', 'w', '2185', '6283', '8457', '8137', '7163', '8329']

Answer: a, b, c, g, m, r, t, w, y, z


Question: ['p', '5229', '7521', 'y', 'n', 'u', 'c', '4047', '781', 'a', '4707', '7149', 'j', 'm', 't', '515', '7691', 'h', '4879', 'j', '6593', 'n', 'p', '2949', '1343', 'y', '2629', 'p', 'b', 'b', '2861', 'a']

Answer: a, b, c, h, j, m, n, p, t, u, y


Question: ['3511', 'i', 'z', 'x', '1761', '5977', '3111', 'b', '8255', 'a', 'g', 'y', '5987', 'q', 'n', 'y', 'j', 'k', 'w', 'a', '2249', '4719', '7533', '7455', 'y', 'q', 'o', '5947', 'l', '2543', 'f', '3867', 'y', 'y', 'l', '1725', '6257', 'k', '4387', 'd', '3149', '3871', 'z']

Answer:
a, b, d, f, g, i, j, k, l, n, o, q, w, x, y, z