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:
['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:
['f', 'a', 'r', '4009', 'k', 'a', 'g', '7725', 'v', 'b', '6705', 'a', '6583', '3159', 'c', 'w', 'x', 'h', '7625', 'p', 'y', '5645', 'k', 'r', 'j', '4175', 'r', '3103', '8631', '5999', 'p', 'g', 'h']
answer:
a, b, c, f, g, h, j, k, p, r, v, w, x, y


question:
['4191', '9227', 'j', 'w', '5279', '3325', '2921', '2053', '7615', 'm', '9987', 'l', 'f', '8563', '4957', '1795', '5463', '4651', 'm', '6421', 's', 'b', '7887', 'x', 'g', '2279', '1539', '1631', 'r', '3447', '2361', '2153', '2269', 'w', 'n', 'w', 's']
answer:

b, f, g, j, l, m, n, r, s, w, x