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]: ['6411', 'x', 'i', '267', 'z', 'e', '5483', '8033', '3697', 'z', '4167', 'e', 'f', '7229', 'i', 't', '2197', 'g']
[A]: e, f, g, i, t, x, z


[Q]: ['k', 'n']
[A]: k, n


[Q]: ['9037', '7021', '9033', '9953', 'q', '6097', 'h', '6521', 'e', 'y', '6887', '5847', 'r', 'p', '6617', '6871', '233', 'b', '1861', 'r']
[A]:
b, e, h, p, q, r, y