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]: ['w', '1367', '5389', '9515']
[A]: w


[Q]: ['7591', '1403']
[A]: -1


[Q]: ['45', '6415', 'i', 'n', 'k', 'w', 'i', 'f', '6323', '115', 'o', '7773', '693', 'y', 'k', 's', '1785', '1207', 'x', 'h', '741', '1175', '2519', '5367', '2267', 'n']
[A]:
f, h, i, k, n, o, s, w, x, y