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.

[EX Q]: ['9947', '3353', '8643', '4621', '4857', 'y', '7075', 'c', '8911']
[EX A]: c, y

[EX Q]: ['v', '5433', 'v', '6749', '7491', 'i', 'm', 'e', '5815', '8423', '833', '7359', 'm', 'i', 'f', 'u', 'p', 'j', 't', '3171', '6165', 'q', 'a', '9475', 'm', 'q', '5995', '8443']
[EX A]: a, e, f, i, j, m, p, q, t, u, v

[EX Q]: ['9117', '1153', 'f', 'b', '9979']
[EX A]:
b, f

