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]: ['6143', 'y', '5505', '9813', 'r', 'v', 'u', '8681', '2387', 'u', 'o', 'm', '9793', 'm']
[EX A]: m, o, r, u, v, y

[EX Q]: ['9013', 'e', 'm', 'p', 'k', '161', 'k']
[EX A]: e, k, m, p

[EX Q]: ['p', 'p', '9829', 'c', '4133', '9227', 'r']
[EX A]:
c, p, r