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: ['895', '2049', '8839', '1773', 'v', '467']

A: v
****
Q: ['a', 'a', 'b']

A: a, b
****
Q: ['3025', 'k', '6949', 'b', '6861', '4223', 'g', '4483', 'q', 'o', 'a', 'x', '2317', '2181', '8293', '7233', '6209', '4849']

A:
a, b, g, k, o, q, x
****