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]: ['565', 'i', '615', '3047', 'm', '195', '7547', '3003', '9213', '9063', 'c', '5099', 'v', '5003', '9053']
[EX A]: c, i, m, v

[EX Q]: ['5971', 'x', 'c']
[EX A]: c, x

[EX Q]: ['4739', '4761', 'b', '1619', '2139', '7297', 'q', '2975', '4989', 'q', '8221', '9945', 't', '9371', 'i', 'q', 'g', '8779', 'k', 'p', 'h', '407', 'o', 'b', 'q', '1571', '9993', '5211', '8341', 'f', 'e', '2899', 'n', '5591', '1969', 'o']
[EX A]:
b, e, f, g, h, i, k, n, o, p, q, t