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]: ['w', '1367', '5389', '9515']
[A]: w


[Q]: ['9351', 'v', 'h', 'z', 'g', 'f', 't', 'q', 'g', 'o', '4073', 'n', '6149', '1735', '157', 'm']
[A]: f, g, h, m, n, o, q, t, v, z


[Q]: ['3561', 'd', '9697', 'd', '7761', 'a', '2833', 'c', '2921', 't', '691', 'g', '4797', 'b', '3913', 'f', 'q', '7807', 'j', '3577', 'j', '1775', '2897', '2589', '993', '8595']
[A]:
a, b, c, d, f, g, j, q, t