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', 'w', '8949', '4025']

Answer: s, w


Question: ['y', '8115', 'f', '5333', 'f', '3437', 'b', 'e', '5719', 'm', 'w', '95', '4863', 'k', '4895', 'a', '8179', 'm', '7919', '1731', '229', 'r', '1847', '7559', '6669']

Answer: a, b, e, f, k, m, r, w, y


Question: ['s', '3207', '6385', '9263', 'h', '1385', 'q', '5277', 'r', 'e', 'h', 'v', '8255', '6903', 'c', 'j', '1071', 'h', 'a', 'l', 'h', '801', '4287', '9607', 'b', '3887', '1327', 'y']

Answer:
a, b, c, e, h, j, l, q, r, s, v, y