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: ['s', 'j', '6779', '1535', 'd', 'e', 'u', '3023', '241', '9115', 'h', '8003', '3755', 'q', 'm', '2725', 'x', 'y', 'n', 'm', 'j']

Answer: d, e, h, j, m, n, q, s, u, x, y


Question: ['g', '7517', '3173', 'd', '2143', 'n', '8507', 'l', '8369', '225', 'e', 'l', '9511', 'p', '1317', '5651', 'p', '1125', 't', '739', '6453', 'l', 'g', '8555', '8075', 'x', 's', 'd']

Answer: d, e, g, l, n, p, s, t, x


Question: ['369', 'g', 'f', 'n', '719', '1091', '5781', '8291', 'v', 'm', 'u', '9841', 'f', 'c', 'a', '8251', 'x', 'p', 'u', '6473', 'g', '3707', 'c', 'z', '6497', 't', '9865']

Answer:
a, c, f, g, m, n, p, t, u, v, x, z