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]: ['u', 'd', '4193', '5687', 'p', 'r', '7787', 't']
[A]: d, p, r, t, u


[Q]: ['h', 'g', '4563', 'v', 'm', '107']
[A]: g, h, m, v


[Q]: ['p', '8535', '7291', '1805', '5859', 'e', 'w', 'p', '2389', '2217', 'f', '5915', '1923', '1613', '2785', '277', '5689', 'r', 'p', 'w', 'o', '9983', 'b', 'g', '3589', '1421', 'l', 'e', 'e', '2013', 'n', '9357', 'i', 'q']
[A]:
b, e, f, g, i, l, n, o, p, q, r, w