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]: ['b', 'd', '8153', 'u', '3695', '5317']
[EX A]: b, d, u

[EX Q]: ['5761', '2289', '577', 't', '125', 'i', 'g', '9693', '747', 'd', '4829', '9587', 'f', 'k', 'w', 'v', '8607']
[EX A]: d, f, g, i, k, t, v, w

[EX Q]: ['9143', 'y', '9925', '267', '469', 'y', 'z', '9305']
[EX A]:
y, z