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]: ['j', '425', '6223', '6631', 'y', '7649', 'r', 'a', '7933', '7947', 'l', 'l', '8755', 'g', 'b', '3351', '49', 'v', 'm', 'x', '3291', '1007', '1401', 'z', 'q', 'a']
[A]: a, b, g, j, l, m, q, r, v, x, y, z


[Q]: ['4213', '3595', '7937', 'y', '5723', 'v', 'b', '7007']
[A]: b, v, y


[Q]: ['7665', 'r', '9269', 'j', 'k', 'j', 'k', 'o', 'l', '1277', 'u', '5837', '5827', '3089', '857', 'w', 'y', '1825', '883', '1803', 'v', '3311', '8207', '7603', 'i', 'z', 'v', 'z', 'f', 'k', 'a']
[A]:
a, f, i, j, k, l, o, r, u, v, w, y, z