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: ['231', 'r', '5673', 'j', '589', 'z', '4659', 'a', '3763']

Answer: a, j, r, z


Question: ['d', 'p', 'k', '9679', 'x', 'j', '7481', '1815', 't', 'w', '6513', 'j', '5079', '5219', 'p', '9545', 'a', '1931', '9973', '8125', '5169', '2791', 't', 'd', '2057', 'e', 'x', 'y', '7409', 'u']

Answer: a, d, e, j, k, p, t, u, w, x, y


Question: ['3529', 'd', 'u', '2441', '9531', '3093', '2989', '6903', 'v', '6521', '9983', 's', 'e', '7809', '6835', 'b', '3625', 'o', '1865', 'e', 'p']

Answer:
b, d, e, o, p, s, u, v