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:
['w', '5341', 'b', '6243', 'v', '877', '1087', '6763', '5241', '3369', '9119', 't', 'v', 'j', '8261', 'o', 'b']
answer:
b, j, o, t, v, w


question:
['t', 'b', '5085', 'c', 'i', 't', '2893', '6367', 'p', '1193', 'u', '9009', '6597', 'i', 't', 'c', '7267', 'a', 'w', 's', '8681', 'g', 'r']
answer:

a, b, c, g, i, p, r, s, t, u, w