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.

Q: ['5463', '5683', 'w', '4071', '3997', 'i', '9677', 'q', 'l', 'v', 'w', '5325', '197', 'g', 'g', '3227', '3477']

A: g, i, l, q, v, w
****
Q: ['7997', 'm']

A: m
****
Q: ['1177', '7057', 'f', 'd', 'g', 'y', 'l', '7361', '21', 'g', 'b', 'f', 'b', '531', 't', 'x', 'a', '1581', 'g', 'h', 'x', '733', 'r', '147', '5675', '3321', 'a', '7531', '4413']

A:
a, b, d, f, g, h, l, r, t, x, y
****