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]: ['p', '9641', '8515', '1207', 'd', 'j', '6617', '5529', 'g', 'a', 'o', 'f', 'y', '4993', '4643', '6087', 'n', '3177', 'y', '9471', '1229', '8211', '7079']
[A]: a, d, f, g, j, n, o, p, y


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


[Q]: ['6847', 'u', 'g', 'x', 'v', '2285', '8559', 'b', '5635', '227', 's', 'u', 'w', '9739', '1265', 'y', 'd', 'e', 'h', '7165', '9237', 'd', 'm', '7641', '4853', 'v']
[A]:
b, d, e, g, h, m, s, u, v, w, x, y