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: ['o', 'c', '6469', 'x', '8815', '4441', '6193', 'u', 'm', 'a', '9879', 'p', '8335', 'c', 'z']

Answer: a, c, m, o, p, u, x, z


Question: ['1979', 'b', 't', '1101', '7953', '2451', '7539', '6833', 'u', '49']

Answer: b, t, u


Question: ['g', '5607', 'p', '8931', 't', '751', 'q', '5877', '5217', 'a', 'n', 'e', 'v', 's', 'p', 'b', '2147', 'e', 'y', '3717', 'o', '3459', 'v', 'n', '4721', 'c', '5683', 'y', 'v', '3129', 'h', '2323', 'q', '8387', '9697', 'y', 'l', 'a', 'r', 'a', '8331', '4011', '1823', '5617']

Answer:
a, b, c, e, g, h, l, n, o, p, q, r, s, t, v, y