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.
--------
Question: ['7055', '2573', '1713', 'x', 'm']

Answer: m, x


Question: ['e', 'c', '4241', '2685', 'o', '9859', 'z', '2647', 'b', 'c', 'y', '1985', '5985', '5709', '6655', 'q', 'z', '9933', '6817', '6477', '1837', 'x', 'p', '9251', '3787', 'v', '5741', 'e', 'p', '493', '5949', '5519', 'v', 'g', '1403', 'z', 'h', 'z']

Answer: b, c, e, g, h, o, p, q, v, x, y, z


Question: ['y', '8743', '4759', '6105', '785', '8031', '5621', '4281', '9701', '9085', '4993', 'b', 'm', 'h', '783', '1997', '6379', '9845', 'q', 'x', '9769', 'p', 'j', '7075', 'y', '7009', '2579', '8785']

Answer:
b, h, j, m, p, q, x, y