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.

['9947', '3353', '8643', '4621', '4857', 'y', '7075', 'c', '8911']
c, y

['d', 'o', '7643', '9065']
d, o

['4339', '6521', 'f', 'v', '2293', '2137', '539', 't', 'l', 'h', '3595', '5005', '7949', '9999', '9607', '2817', '1323', '5713', '1573']

f, h, l, t, v