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: ['k', 'n']

Answer: k, n


Question: ['9627', '9879', '5421', '4755', '1533', '6727', 't', '7641', 'd', '3929', 'h', '3989', '8441', 'k', 'p', '2653', 'm', 'b', 'i', '3431', '4907', '5687', 'g', 'h', '9185', '5051', 'k', '7135', '709']

Answer: b, d, g, h, i, k, m, p, t


Question: ['r', 'u', '1289', '7099', 's', '4159', '8655', 'a', 'g', '5157', 'x', 'e', 'g', 'z', '1033', '9005', '6205', 's', 'y', 'e', '9203', 'z', 'n', '3793', 'e', 'b', '8713', '6867', '7743', '2007', '2165', 'f', '2621', '579', '1521', '1543', 'l', '4709', 'z', '7881', '9041', '705', '2245']

Answer:
a, b, e, f, g, l, n, r, s, u, x, y, z


