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: ['f', '9203', 'w', 'f', '3751', '8095', '1319', 'f', '3017', 'r', 'y', '8221', '2715', '9959']

Answer: f, r, w, y


Question: ['5957', 'd', 'i', 'b', 'e', '5565', 'c', 'i', '2919']

Answer: b, c, d, e, i


Question: ['7723', '1121', '3181', '1197', '8037', '4351', 'a', 'm', 'j', 'a', 'g', '529', 'q', '9577', 'n', '6981', 'n', 'z', 'x', 'w', 'a', '9243', 'v', 'a', '9063']

Answer:
a, g, j, m, n, q, v, w, x, z