instruction:
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.
question:
['q', 'h', 'q', '7185', 'f', 'l', 'r', '3605', 'x', 'i', 'v', '8789', 'u', 'x', 'x', '8315', 'x', 't', 'h', 'o', '4943', '5827', '7677']
answer:
f, h, i, l, o, q, r, t, u, v, x


question:
['2381', 'y', '6631', '5839', 'r', 'm', 'z', 'b', '4663', '595', '7771', '5305', '5087', '3317', '3125', '9551', '4343', '5121', 'm', 'i', '131', '8401', '5379', '1775', 'u', '1125', '9793', '4123', 'h', '1613']
answer:
b, h, i, m, r, u, y, z


question:
['s', '8127', '8401', 'b', '2189', 'p', '6071', 'v', '8975', '6591', '2779', '2095', 'e', '1367', '2833', '7307', '9837', '2115', 'q', 'w', '9141', '9757', '9629', '4015', 'v', 'e', '6347', '2895', '3625', '4767', '9117', '8995', '3497', '9389', 'x', '263']
answer:

b, e, p, q, s, v, w, x