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:
['z', 'h', '2065', '6773', 'v', '151', '8957', 't', 'l', 'j', '7867', 'v', '799', '9009', '4317', 'm', '6921', 'r', '1245', '5637', 'x', '4465', 'f', 'y', '3549', 'e', 'f', 'm', 't', '6281', '4241', '3415', 'z', 'g']
answer:
e, f, g, h, j, l, m, r, t, v, x, y, z


question:
['1345', 'y', '7221', 'h', 'r', '3255', 'k', 'r', 'j', '8639', '467', 'f', 'k', 'n', 'k', 'j', 'l', 'w', '143', 'w', 'q', '5657', '589']
answer:
f, h, j, k, l, n, q, r, w, y


question:
['v', '9041', 'b', 'r', 'b', '5847', 'w', 's', '3261', '9983', '3641', '2585', 't', '1157', 'e', '6103', 'u', 'l', '2689', 'h', '1485', 'u', '9153', 'g', 'f', '4223', 'i', 'n', '3851', 'l', 'a', '2883', '2555', 'q', 'z', '7087', '7491', '6537']
answer:

a, b, e, f, g, h, i, l, n, q, r, s, t, u, v, w, z