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: ['d', '1625']

A: d
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Q: ['7187', '7081', 'j', 'i', '3725', '6333', 'h', 'f', '6639', 'r', 'n', '3559', '2785']

A: f, h, i, j, n, r
****
Q: ['7269', '2907', '6355', 'x', '2515', 'v', 'n']

A:
n, v, x
****