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', 't', '2901', '9697', 'a', 'j', 'x', 'a', '4437', '2255', '2177', 's', '3173', 'j', 't', '5713', '4091', '4253', '5553', 'i', '4533', 'i', 'e', '6899', 's', '3541', '2139', '2705', 'm', 'u']

Answer: a, e, i, j, m, n, s, t, u, x


Question: ['6209', 'x', 'j', 'w', '7965', '4905', '6297', '4291', '7183', 'a', 'l', '5267', 'r', '5935', 'a', '7865', 'h', 'p', '6117', 'a', 'y', 'y', 't', 'v', '7271', 'e', 'e', 'z', 'i', 'l', '4731', '2059', 'm', '5703', 'k', 'f', '8125', 'e', '7569', 'r', '2287', '593']

Answer: a, e, f, h, i, j, k, l, m, p, r, t, v, w, x, y, z


Question: ['a', 'u', '2349', 'y', '4925', '1155', 'h', 's', '9025', '5235', '4427', '3697', 'h', 'y', 'i', 'n', 'd', 'o', '8169', '8969', 'p', 's', 'j', 'v', 'a', '305', '4619', '2717', 'h', '3953', '9601', '4349', '789', 't', 'x', 'c', 'v', 'b', 'g']

Answer:
a, b, c, d, g, h, i, j, n, o, p, s, t, u, v, x, y