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.

[EX Q]: ['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']
[EX A]: b, d, f, g, h, i, k, l, p, r, t, u, w, x, y, z

[EX Q]: ['1429', '7273']
[EX A]: -1

[EX Q]: ['e', 't', 'w', '8643', '2683', 'v', 'f', 'p', '3297', 'n', 'n', 'w', '4415', 'z', '1907', 'z', '2057', '5553']
[EX A]:
e, f, n, p, t, v, w, z