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]: ['4749', '4607', '625', '6907', 't', 'b', '8479', '6505', 'r']
[A]: b, r, t


[Q]: ['d', 'o', '7643', '9065']
[A]: d, o


[Q]: ['9697', '101', '13', 'b', 'h', '3013', '6799', 'q', '8841', '4727', 'r', 'x', 'b', 'h', 'd', 'h', '5939', '4175', '4611', '9305', 'u', '7181', 'p', 'k', '5987']
[A]:
b, d, h, k, p, q, r, u, x