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: ['n', 'g', 'u', '2873', 'k', '4411', 'w', '8179', 'w', 'w', 'f', 'g', 'e', '7837', '3055', 'z', 's', '6037', 'n', '1479', 'c', '5311', 'i', 'w', 'z', '1891', '9663', 'y', 'f', 'h']

Answer: c, e, f, g, h, i, k, n, s, u, w, y, z


Question: ['1449', 'a', '6261', '303', '4651', 'n', 'u', '1595']

Answer: a, n, u


Question: ['b', 'h', '2773', 'l', 'g', 'e', 's', 'e', '3989', 'l', 'p', 'd', 'k', '4613', '9423', 'y', '6747', 'g', 'g', 'l', 'w', 'k', '5117', 'p', '8909', 'z', 'g', '4519', '2503', '5175', 'c', '1961', 'v', '4217', '9563', 'n', 'j', 's']

Answer:
b, c, d, e, g, h, j, k, l, n, p, s, v, w, y, z