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:
['395', '8309', 'v', 'r', 'x', 'j', 'l', 'b', 'c', 'c', '3123', 't', 'a']
answer:
a, b, c, j, l, r, t, v, x


question:
['w', 'i', '4383', '7667', '9617', 'y', 'a', '8051', 'w', '4857', 'y', '3953', 'u', 'o', 'y', 'i', '9201', 'g', '1807', '5367', 'g', '5263', '3995', '6665', '3113', '9433', '6315', 'm', '845', 'x', 'c', 'v', 'h', '1491', 'g', '3519', 'x', 'b', '7695']
answer:
a, b, c, g, h, i, m, o, u, v, w, x, y


question:
['q', '5263', 'g', 't', '7675', 'a', 't', 'g', 'o', '3909', 'q', '5701', '2817', '2405', 's', '4915', 's', 'x', '2633', '3481', 'w', '7875']
answer:

a, g, o, q, s, t, w, x