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]: ['l', 'g', 'd', 'p', '8163', '6643', 'o', 'p', 'm']
[EX A]: d, g, l, m, o, p

[EX Q]: ['6769', '1057', '1021', 'n', '8231', '9173', '8123', 'a', '6053', 'q', 'y', '883', 'r', '1215', 'x', 'o', '9531']
[EX A]: a, n, o, q, r, x, y

[EX Q]: ['o', '1851', 'a', 'k', 'e', 'z', 'h', 'q', '3507', 'l', '9929', '9361', 'm', 'w', '9393', 'l', '883', '1829']
[EX A]:
a, e, h, k, l, m, o, q, w, z