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:
['9113', '3625', 'u', '8189', '3649', '259', '5539', '1583', 'g', '4037', 'y', 'v', '8337', 'd', 'q', 'j', 'c', 'h', 'p', '1601', 'z', 'c', 'n', '1767', '1679', '1805', 'm', '4469', '2487', '6015', '973']
answer:
c, d, g, h, j, m, n, p, q, u, v, y, z


question:
['l', '6313', '3199', 'w', '249', '8747', '7391', '3871', '173', 'x', 'o', '8647', '4413', '3645', '6123', '701', 'q', '2147', '4289', '7333', '533']
answer:
l, o, q, w, x


question:
['w', '5745', '1655', 's', '8151', '3379', 'c', 'g', '4835', '8795', '5801', '1269', '961', '9409', 'r']
answer:

c, g, r, s, w