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:
['c', '9125', '6049', '5201', 'v', '9311', 'q', '3305', 'l', 'q', '3387', '3647', 'x', '471', 'a', '5631', 't', '9679', '5423', '2569', 'w', 't', '6397', 'e', 'h', 'c', 'v', 'v']
answer:
a, c, e, h, l, q, t, v, w, x


question:
['5489', 'f', '6833', 's', 'c', '6575', 'w', '2957', '8465', 'v', 'h', '2119', '7731', 'e', '5367', 'e', '3357', 'p', '7565', 'n', 'x', 'n', 'f', '1075', '5941', '6505', 'j', 'p', '2853', 'l', 'q', '4727', 's']
answer:
c, e, f, h, j, l, n, p, q, s, v, w, x


question:
['1919', '3221', '4365', '4337', 'd', '9947', '6931']
answer:

d