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:
['u', 'i', '1185', '3795', '5417', 'k', 'b', '2629', '2635', 'z']
answer:
b, i, k, u, z


question:
['219', '2065', '4045', 'k', 'n', 's', 'z', '7239', '1043', 'r', '2333', 'q', 'k', 'b', '2013', 'g', '6925', '9835', 'a', '5377', 'k', '8005', 'p', '9753', 'm', '201', '2353', 'f', 'n', '89', 'q', 'p', '7847', 's', 'l', '3359', '2269', 'v', 'm', '8247', '9665', 'u', 'w']
answer:
a, b, f, g, k, l, m, n, p, q, r, s, u, v, w, z


question:
['5819', 'r', '4983', '9187', '8087', 'g', '5391', '4247', 'g', 'n', 'z', 'p', '2677', 'm', 'e', '8411', '4237', '2489', 'y', 'l', 'z', '2461', '4137', '803', '5251', '2233', '551', '2925', 'x', 'k', 'd']
answer:

d, e, g, k, l, m, n, p, r, x, y, z