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.

['2915', '6033', '5541', '4685', '1263', '6701', 's', '7269', 'g', '8033', '8171', '6917', 'l', '2913', '447', 'g', 'a', 'z', 'o', '7563', '5385', '5259', '5067', '4869', '2653', '6925', '7001', '8553', 'x', '1243', '9131', '5037']
a, g, l, o, s, x, z

['2505', '4199', 'e', '5433', '8795', 'q', 'i', '9357', 'o', '257', '8235', 'b', '1339', 'w', '1463', 'm', '277', '3211', '3863', 'r', 'm', 'i', '5793', '7451', '4787', '4739', 'k', 't', 'o', '7453', '9385', 'v', 'l', 'y', 'f', 'r', 'p', 'w']
b, e, f, i, k, l, m, o, p, q, r, t, v, w, y

['e', '2783', 'o', 'r', 'f', 'u', '193', '5749', 'e', 'g', 'f', 'i', 'z', '2855', 'x', 'a', 't', '3835', '3421', '361', 'm', '7217']

a, e, f, g, i, m, o, r, t, u, x, z