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]: ['1707', '381', '3957', '7853', '4987']
[A]: -1


[Q]: ['1447', 'q', '9529', '2971', 's', '7351', '6753', '3493', 'v', 'c', 'x', '3097', '9145', 'b', 'e', 'b', '2967', '6933', 'e', 's', 'v', 'f', 'z', 'r']
[A]: b, c, e, f, q, r, s, v, x, z


[Q]: ['5817', '7741', '6407', 'q', 'p', 'r', 'p', 'd', 'e', 'r', '325', '5969', '2895', '5747', 'a', 'o', '2427', '5853', '3031', '449', 'j', '2299', '2737', 'r', '9995', '6825']
[A]:
a, d, e, j, o, p, q, r