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]: ['7071', 'h', '837', 'z', 'c', '2217', 'c', '6341', '6607', 'g', '3569', 'a', 'h', 't', 'b', 'f', 'g', 'f', 'l', 'b', 'x', 'o', 'r', '8949', '8071', '1507', 'v']
[A]: a, b, c, f, g, h, l, o, r, t, v, x, z


[Q]: ['s', '2507', '3091', 'g', '7643', '2573', 'w', 'r', '1977', 'q', 'c', 'j', '1335', '9671', '7317', '567', '2041', '5777', 'w', 'm']
[A]: c, g, j, m, q, r, s, w


[Q]: ['r', 'b', 'x', '5795', '763', 'f', '517', '6199', 'j', '6379', '4061', '4835', 'l', '2891', 'a', '7467', '5103', 't']
[A]:
a, b, f, j, l, r, t, x