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.

['f', 'p', 'n', '839', '9229', 'r', '7661', 'c', '4383', 'u', 'k', '5321', '3181', '1785', 'w', 'k', '8721', '7855', '4093', '6495', 'q', '2467', 'g']
c, f, g, k, n, p, q, r, u, w

['u', 'w', '401', 't', 'g', 'h', 'g', '8073', '9597', '1347', '7835', '5007', '977', 'p', '7679', 'b', '4883', '4931', '999', 'r', '1181', 'x', '2063', 'l', 'w', 'i', 'l', 'x', 'i', '9057', '5007', 'w', '743', '1635', 'y', 'f', '9227', 'z', '5227', 'd', '7129', 'k', '7657']
b, d, f, g, h, i, k, l, p, r, t, u, w, x, y, z

['z', 'n', '5967', 'b', 'l', 'v', 'l', '2641', '2375', 'w', '3289', '1531', 'e', '6509', 't', 'o', '3811', '6825', '5899', 'n', 'd', 'o', '8815', 'q', 'c', '4711', '5893', 'b', '1705', 'c', '8881', '9537', '6297', '981', 't', '5411', '5865', 'x', '8013', '1483', '5803', '7791', '5987', 'j']

b, c, d, e, j, l, n, o, q, t, v, w, x, z