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: ['o', 'm', '8015', '787', '4787', '1727', 'f', 'e', 'c']

A: c, e, f, m, o
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Q: ['a', 'w', 'm', 'g', 'c', '5475', '7391', 't', '1049', 'p', 'd', '1397', 'k', 'x', 'j', '2525', 'f', '741']

A: a, c, d, f, g, j, k, m, p, t, w, x
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Q: ['i', '1129', 'f']

A:
f, i
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