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.

[EX Q]: ['815', '6967', '6553', 'r', 'y', '3641', 'q', 'b', '6131', '4289', 'w', '6093', '6055', 'i', 'b', 'y', '5107', 'v', 'g', '9709', 'x', 'i']
[EX A]: b, g, i, q, r, v, w, x, y

[EX Q]: ['4009', 'y', '9077', 'p', 'q', '6711', '6443', '5491']
[EX A]: p, q, y

[EX Q]: ['y', '8039', '5829', '8685', 'o', '2765', 'c', '7065', '5509', '8825']
[EX A]:
c, o, y