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:
['4927', 'h', 'x', '4719', 'j', 'f', '7797', 'l', 'i', 'q', 'x', 'i', 'k', '3215', 'k', '1625', 'g', 't', 'i', 'w', 'n', '6659', '8355', '831', 'h', '9723']
answer:
f, g, h, i, j, k, l, n, q, t, w, x


question:
['e', 'c', '4241', '2685', 'o', '9859', 'z', '2647', 'b', 'c', 'y', '1985', '5985', '5709', '6655', 'q', 'z', '9933', '6817', '6477', '1837', 'x', 'p', '9251', '3787', 'v', '5741', 'e', 'p', '493', '5949', '5519', 'v', 'g', '1403', 'z', 'h', 'z']
answer:
b, c, e, g, h, o, p, q, v, x, y, z


question:
['9803', '5755', '9711', '9507', '7047', 'k', '1681', 'a', 'm', 'l', '2783', 'v', '6837', '6311', '1225', '8663', 'm', '4097', 'n', 'f', 'y', 'r', 'n', '2645', '9869']
answer:

a, f, k, l, m, n, r, v, y