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.

['9947', '3353', '8643', '4621', '4857', 'y', '7075', 'c', '8911']
c, y

['r', 'q', '3649', 't', '3941', 'z', '3729', 's', 'g', '6905', 'h', 'v', '1085', '6353', 'a', '9395', '5433', 'a', '2565', 'p', 'a', 'h', '1491', 'j', 'b', 'v', 'e']
a, b, e, g, h, j, p, q, r, s, t, v, z

['9663', 'v', '8999', 'g', 'g', 'e', 'l', 'n', 'n', '3827', '6629', '1105', 'n', 'r', '6357', 'p', '151', '1305', 'k', 'd', '6187', '983', '4583', '5111', 'j', '281', 'g', 't', '2521', '437', '7581', 't', '5513', 's', 'u', '725', 's', '2663']

d, e, g, j, k, l, n, p, r, s, t, u, v