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: ['d', '771', '4193', 'e', '1537', 'a', 'q']

Answer: a, d, e, q


Question: ['e', 'r', 't', '9825', '7581', '2755', '2757', 'd', 'z', '3211', '9599', '5195', '125', 'b', 'p', 'f', '4403', '5241', 'q', '3763', '4101', 'o', 'n', 'v', '5857', '1661', '4997', 'e', 'a', '4457', 'o', '6829', '5167', 'm', 'z', '1263', 't', 'n', '5009', 'z', '6259']

Answer:
a, b, d, e, f, m, n, o, p, q, r, t, v, z