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: ['4041', 'l', 'g', '9571', '9295', '1395', 'l', 'p', 'f', 'w', 'g', '1721', '2421', 'w', 'z', '2235', 'p', '7851']

Answer: f, g, l, p, w, z


Question: ['w', 'n', '729', '2491', 'n', 'x', '915', '1869', 'z', '8491', '9947', '561', '829', 'n', 't', 'i']

Answer: i, n, t, w, x, z


Question: ['r', 'g', 'z', 'c', '787', '8183', 'a', '1319', 'z', 'i', '2101', '2759', 'b', '5947', '5365', 'q', 'k', 'p', '8559', 'j', 'u', '6191', '7753', 'v', 'f', 'a', 'v', '337', 'n', '3567', 't', 'k', '493', '3057', 'w', 'w', '7069', 'a', '8685', 'u', 'y', 'l', 'e', '6121', '1865']

Answer:
a, b, c, e, f, g, i, j, k, l, n, p, q, r, t, u, v, w, y, z