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.

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

['2409', 'q', 'w', 'e', 'x', '4737', 'w']
e, q, w, x

['v', 'm', '6847', '8327', 'n', '1491', '9523', 'h', 's', '2861', '1471']

h, m, n, s, v