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]: ['3147', '9807', '5313', '6311', '737', '1555', '5803', '3437', '5665', '3973', 'o', 'f', '7871', '1721', '7833', '2933', 'b', 'b', 'n', 'm', 'k']
[A]: b, f, k, m, n, o


[Q]: ['z', '3219', '6399', '2357', '7597', '357', 'k', 'k', 'u', 'd', '6115', 'w', '2921', '8809']
[A]: d, k, u, w, z


[Q]: ['d', 's', 'c', '6727', '5865', '4789', '3091', '7747', 'd', 'k', '4139']
[A]:
c, d, k, s