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: ['i', '9215', 'n', 'p', '4815', '8757', 'm', '1755', 'c', 'z']

Answer: c, i, m, n, p, z


Question: ['h', 'v', '1263', 'y', '3299', 'd', 'a', 'h', 's', '2007', '7597', '1015', 'k', '6643', '6959', 'g', 'u', 'd', '5737', 'n', 'z', 'y', 'b', 'g', '9059', '7349', 'j', 'w', 'i', 'z', 'p', '5809', 'x', '4421', 'g', '6399', '3965']

Answer: a, b, d, g, h, i, j, k, n, p, s, u, v, w, x, y, z


Question: ['2259', 'n', 'x', 'i', 'f', 'w', 'r', 'u', 'p', '5701', '1643', '4161', '4343', 'n', 'h', '4419', 'n', 'i', '7349', '7109', '8949', '9025', 'h', 'l', '713', '1799', '5989', 'b', 'n']

Answer:
b, f, h, i, l, n, p, r, u, w, x