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]: ['d', '771', '4193', 'e', '1537', 'a', 'q']
[EX A]: a, d, e, q

[EX Q]: ['6411', 'x', 'i', '267', 'z', 'e', '5483', '8033', '3697', 'z', '4167', 'e', 'f', '7229', 'i', 't', '2197', 'g']
[EX A]: e, f, g, i, t, x, z

[EX Q]: ['u', '357', '9553', 'o', '2841', '9221', '3317', 'q', '2179', '8411', 'p', 'r', 'a', '8611', '883', '1445', '4163', '3575', 's']
[EX A]:
a, o, p, q, r, s, u