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.

['l', '6819', '1029', '2925', '2361', '5545', '2151', '2681', 'f', 'p', '1263', '2875', 'b', '4665', 'f', 'g', 'p', '4829', '8453', 'z', 'l', '4219', '7517', '25', 'a', '5099', '3693', 'i', '1815', '1541', 'g', '7665']
a, b, f, g, i, l, p, z

['4927', 'h', 'x', '4719', 'j', 'f', '7797', 'l', 'i', 'q', 'x', 'i', 'k', '3215', 'k', '1625', 'g', 't', 'i', 'w', 'n', '6659', '8355', '831', 'h', '9723']
f, g, h, i, j, k, l, n, q, t, w, x

['1655', '1321', '9109', 'z', '7321', 'p', 'b', '5323', 'j', '5089', '2287', 'n', 'h', '9359', '8659', 'f', '3017', '3287', '3757', 'q', 't', '9931', 'p', 'f', '8667', '9223', 'g', '921', '7235', 'k', '8339']

b, f, g, h, j, k, n, p, q, t, z