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:
['7203', '8715', '3193', 'w', '7159', '8535', 'i', '2425', 'j', 'f', '6709', 'w', 'w', 's', 'e', '9337', 'r', 'r', '5255', '1707', 'u', '1443', 'e', 'e', 'v']
answer:
e, f, i, j, r, s, u, v, w


question:
['b', 'a', '7411', '4471', 'z', 'l', '2051', 'q', '6749', '8647', 's', 'y', 'h', '9319', 'e', '5419', 'y', 'q']
answer:
a, b, e, h, l, q, s, y, z


question:
['9869', '9995', 'p', 'r', 'j', '5629', '2165', '4811', 'a', 'b', '6273', 't', '1037', 'e', '2849', 'q', 'd', 'w', '9465']
answer:

a, b, d, e, j, p, q, r, t, w