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:
['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:
['6249', '1235']
answer:
-1


question:
['m', '4007', '6259', 'v', 'j', 'c', '3457', '6133', '6913', 'z', '1513']
answer:

c, j, m, v, z