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.

Q: ['9947', '3353', '8643', '4621', '4857', 'y', '7075', 'c', '8911']

A: c, y
****
Q: ['p', '2923', 'e', 'k', '5433', '605', '5079', 'k', 'p', 'x', '4845', '4099', '6795']

A: e, k, p, x
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Q: ['9651', 'd', 'h', '23', 's', 'w', 'e', 'l', '8477', 'g', 'b', 'l', 'r', '5383', 'w', 'i']

A:
b, d, e, g, h, i, l, r, s, w
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