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:
['n', 'g', 'u', '2873', 'k', '4411', 'w', '8179', 'w', 'w', 'f', 'g', 'e', '7837', '3055', 'z', 's', '6037', 'n', '1479', 'c', '5311', 'i', 'w', 'z', '1891', '9663', 'y', 'f', 'h']
answer:
c, e, f, g, h, i, k, n, s, u, w, y, z


question:
['7417', '2597', '2633', '7721', 'v', 'l', 'p', '4389', 'l', '3965', '6279', 'm', 'v', 'o', 'd', 'o', 'h', 'd', 'r', 'e', '8993', '2711', 'o', 'q', '1399', 'i']
answer:
d, e, h, i, l, m, o, p, q, r, v


question:
['4239', '8901', '8579', 'z', '8457', 'g', '965', 'c', '761', '5885', 'h', 'p', '5985', '4881', 'v', 'i', '8785', '9011']
answer:

c, g, h, i, p, v, z


