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]: ['6249', '1235']
[A]: -1


[Q]: ['i', 'x', 'n', 'w', '8915', 'd', 'd', 'd', '6025', '7861']
[A]: d, i, n, w, x


[Q]: ['1447', 'q', '9529', '2971', 's', '7351', '6753', '3493', 'v', 'c', 'x', '3097', '9145', 'b', 'e', 'b', '2967', '6933', 'e', 's', 'v', 'f', 'z', 'r']
[A]:
b, c, e, f, q, r, s, v, x, z