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]: ['g', 'u', 'q', '1375', '9491', 't', 'w', 'c', 'v', 'y', '3169', '1607']
[A]: c, g, q, t, u, v, w, y


[Q]: ['4925', 'i', 'q', 'k', '7615', 'r', '7217', 'o', '8097', '9151']
[A]: i, k, o, q, r


[Q]: ['x', '9571', 'q', 'z', 'h', 's', '2627', '6827', '3265', '2781', '1017', 'g', '7879', 'v', 'j', 'u', 'm', 'u', 'r', '9611', '9339', '3453', 'l', '4375']
[A]:
g, h, j, l, m, q, r, s, u, v, x, z