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]: ['2409', 'q', 'w', 'e', 'x', '4737', 'w']
[EX A]: e, q, w, x

[EX Q]: ['m', '5005', 'y', 'h', 'w', '3609', 'p', '2539', '3307', 'p']
[EX A]: h, m, p, w, y

[EX Q]: ['7049', 't', '2505', 'x', '4479', '7695', 'u', 'u']
[EX A]:
t, u, x