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: ['4213', '3595', '7937', 'y', '5723', 'v', 'b', '7007']

Answer: b, v, y


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

Answer: a, j, r, z


Question: ['x', 'a', 'n', '6221', 's', '525', 'd', '2791', 'p', '5299', 'h', 'q', '5875', 'k', '6395', '7697', 'x', '215', 'v', '395', '3141', 'n', '7459', 'b', '3783', 'm']

Answer:
a, b, d, h, k, m, n, p, q, s, v, x