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: ['4637', 'f', '2639', '8623', 'w', 'e', 'k', '5503', 'x', '6633', '7553', '1455', 'u', '1773', 'r', 'u', '1489', 'u', '1303', '9683', 'z', '565', '7041', 'x', 'z', '9431', 'k', 'v', 'j', 'z', '5469', '5665', '4089', '4951', '8263', '5675', '4095', '7745', 'z', '2437', 'd', 'e', 'w']

Answer: d, e, f, j, k, r, u, v, w, x, z


Question: ['s', 'u']

Answer: s, u


Question: ['619', 'h', 'u', 'v', 'a', 'p', '7425', '5645', 'j', 'b', '2377', '6911', 'n', 'l', '3045', '6623', 'n', '7315', 'c', '8015', 'u', 'n', '2155', '2081', 'j']

Answer:
a, b, c, h, j, l, n, p, u, v