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]: ['k', 'r', 'f', '4369', 'z', 'z', 'l', '143', 'r', '707', '9167', 'g', '1749', 'i']
[A]: f, g, i, k, l, r, z


[Q]: ['9117', '1153', 'f', 'b', '9979']
[A]: b, f


[Q]: ['n', '7095', 'r', 'a', '7349', 'x', '5163', '8299', 'c', 'g', 'd', 'q', '4607', '5529', '5187', '905']
[A]:
a, c, d, g, n, q, r, x