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:
['o', 'd', '6495', '5211', '341', 'v', '385', 'v', 'g', 'v', 'l', '7631', '2675', 't']
answer:
d, g, l, o, t, v


question:
['4857', 'z', '313', '7813', '9935', 'o', 'w', 'i', 'x', 'o', 'e', 's', 'a', 'p', 'i', 'v', 'x', '6743', 'p', '435', 'u', 'a', 'h', '607', '2491', '6159', 'u', '7761', '6197', '3449', '3459', 'e', 'g', '8731', '335', '2883', '3941', 'n', '1881', 'y', 'j', '8189', 'k', '7593', '2747']
answer:
a, e, g, h, i, j, k, n, o, p, s, u, v, w, x, y, z


question:
['6285', '6353', '7423', 'l']
answer:

l