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: ['3395', '7471', 'n', '9537', '1255', '1997', '3085', '4863', '9797', '4275', 'k', 'f', '8973', '3939', 'p', 'q', '4977', '6231', '8745']

A: f, k, n, p, q
****
Q: ['o', 'm', '8015', '787', '4787', '1727', 'f', 'e', 'c']

A: c, e, f, m, o
****
Q: ['4861', 'o', '7061']

A:
o
****