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: ['1979', 'b', 't', '1101', '7953', '2451', '7539', '6833', 'u', '49']

A: b, t, u
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Q: ['d', '2359', '6571', 'c', 'n', 'u', '9513', '9321', '1689', 'b', '969', '1823', 'e', 'b', '9147', 's', '1811', 'k', '5443', '8699', '5483', 'v', 'w', 'n', '1215']

A: b, c, d, e, k, n, s, u, v, w
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Q: ['3957', '6525', 'i', '9057', '233']

A:
i
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