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.

[Q]: ['w', '1367', '5389', '9515']
[A]: w


[Q]: ['e', 'n', 'y', 'f', 'l', 'h', '455', 'y', '591', 'm', '9041', 'b', 'b', 'o', '4215', '5009', 'o', 'a', '4369', 'u', '6911', '4825', 't', 'k', '6063', '2939']
[A]: a, b, e, f, h, k, l, m, n, o, t, u, y


[Q]: ['y', 'n', 'o', '3937', 'w', '5439', '7235', 'r', '841', 'q', '1881', '6131', 'i', 'c', '8903', '8145', '6035', '2591', '8729', '9445', 't', 'l', 'v', '2479', 'c', 'q', 'i', 'j', '1405', 'f', 'n', 'u', '381', 'd', 'j', '6823', '1351', '2087', '6813']
[A]:
c, d, f, i, j, l, n, o, q, r, t, u, v, w, y