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:
['r', 'q', '3649', 't', '3941', 'z', '3729', 's', 'g', '6905', 'h', 'v', '1085', '6353', 'a', '9395', '5433', 'a', '2565', 'p', 'a', 'h', '1491', 'j', 'b', 'v', 'e']
answer:
a, b, e, g, h, j, p, q, r, s, t, v, z


question:
['l', 'g', 'd', 'p', '8163', '6643', 'o', 'p', 'm']
answer:
d, g, l, m, o, p


question:
['9347', 's', '6785', '1591', 'k', 'd', 'l', 'z', 'p', '2713', 'o', '8265', '8161', 'e', '1733', 'e', 'q', 'o', 'd', '9529']
answer:

d, e, k, l, o, p, q, s, z