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: ['277', '8697', 'q', '2023', '5723', 'm', '8673', 'f', 'z', 'z', 'a', '9875', 'p', 'x', 'l', 'z', 'x', '619', '6509', 's', '2067', '571', 't']

Answer: a, f, l, m, p, q, s, t, x, z


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

Answer: a, j, r, z


Question: ['t', '9171', 'z', 'p', 'i', '261', '2001', 'r', '1071', 'v', 'v', 'i', '2291', '3815', '3145', 't', '1361', 'i', '2673', 's', 'j', '6429', 'f', 'f', '6289', 'r', '8897', '2877', 'm', 'j', 's', '3753', 'q', 'u']

Answer:
f, i, j, m, p, q, r, s, t, u, v, z