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: ['1063', 'f', 'm', 'i', 'x', 'i', 'd']

A: d, f, i, m, x
****
Q: ['1429', '7273']

A: -1
****
Q: ['293', '3115', 'g', '4733', '4241', 'b', 'g', 'r', '2169', 'g', 't', 'a']

A:
a, b, g, r, t
****