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:
['907', '2407', '1385', '3593', 'x', '4143', '2271', '8361', 'q', '5093', 'd', '257', 'm', 'a', '5751', '7845', '3925', '3517', '7753', 'e', '5803', '2629', 't', 'e', '845', '6157', '9787', '225', 'j', 'j', 'l', '1321', 'k', '2459', 'u', '9113', '3193', 'a', 'j', 't']
answer:
a, d, e, j, k, l, m, q, t, u, x


question:
['o', '369', 'z', '5721', 'w', 'v', '4973', '7773', 'k', '3071', '5103', '425', '4239', '7977', 'n', 'i', 'k', '8117', '9843', 'n', 'd', '1353', 'h', 'd', 'v', 'z', 'j', '8727', '6997', 'x', '767', '4331', 't']
answer:
d, h, i, j, k, n, o, t, v, w, x, z


question:
['6457', 's', 'e', '2709', 'z', 'j', 'm', 'g', 'p', 'y', 'd']
answer:

d, e, g, j, m, p, s, y, z