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', '9641', '8515', '1207', 'd', 'j', '6617', '5529', 'g', 'a', 'o', 'f', 'y', '4993', '4643', '6087', 'n', '3177', 'y', '9471', '1229', '8211', '7079']
a, d, f, g, j, n, o, p, y

['789', '3603', '3517', '5831', 'z', 'q', 'w', 'l', '5701', '9503', '8169', '1123', 'e', '529', 'j', 'z', 'l', 'o', '3705', 'o', '5131', '6063', 'c', 'j', '6275', '7701']
c, e, j, l, o, q, w, z

['8429', 'v', 's', '8631', 'a', '1863', '4343', '3761', '7407', '2307', 'c', '4955', '5779', 'w', 'p', '5049', '8799', '8671', 'i', 'e', '9201', 'n', 'x', '8001', 's', 'l', 'u', '4273', 'j', 'u', '7269']

a, c, e, i, j, l, n, p, s, u, v, w, x