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.

['p', '5229', '7521', 'y', 'n', 'u', 'c', '4047', '781', 'a', '4707', '7149', 'j', 'm', 't', '515', '7691', 'h', '4879', 'j', '6593', 'n', 'p', '2949', '1343', 'y', '2629', 'p', 'b', 'b', '2861', 'a']
a, b, c, h, j, m, n, p, t, u, y

['4857', 'z', '313', '7813', '9935', 'o', 'w', 'i', 'x', 'o', 'e', 's', 'a', 'p', 'i', 'v', 'x', '6743', 'p', '435', 'u', 'a', 'h', '607', '2491', '6159', 'u', '7761', '6197', '3449', '3459', 'e', 'g', '8731', '335', '2883', '3941', 'n', '1881', 'y', 'j', '8189', 'k', '7593', '2747']
a, e, g, h, i, j, k, n, o, p, s, u, v, w, x, y, z

['p', '1025', 'l', '819', '8055', 'l', 'k', 's', '6465', '2163', 'q', 'd', 'q', 'd', 'z', 'u', '9515', '3005', 'x', '1893', '5825', 'd', '3317', 'y', 'j', '8823']

d, j, k, l, p, q, s, u, x, y, z