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]: ['333', 'b', '261', 'k', 'p', '7861']
[A]: b, k, p


[Q]: ['d', 'p', 'q', '5319', 'w', '4887', '6695', 't', '7711', 'l', '7597', 's', 'n', '1461', 'e', '9045', '1307', 'j']
[A]: d, e, j, l, n, p, q, s, t, w


[Q]: ['673', '2751', 'o', '7189', 'n', '8577', 'a', 'x', '1047', '4757']
[A]:
a, n, o, x