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.

['5345', 'f', '6605', 's', 'q', 'w', 'p', 'o', 's', 'u', 'i', '7339', '8379', 'h', '9547', 'b']
b, f, h, i, o, p, q, s, u, w

['p', '2923', 'e', 'k', '5433', '605', '5079', 'k', 'p', 'x', '4845', '4099', '6795']
e, k, p, x

['2061', '4729', 'i', '3763', '849', 'e', 'y', 'v', '4171', 'u', 'e', '7507', 'r', 'm', '6071', '3205', 'c', '4931', 'b', 'p', '5499', 'g', '8573', '5895', 'm', '9415']

b, c, e, g, i, m, p, r, u, v, y