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:
['3651', 'c', 'm', '7123', '2981', '9649', 'o', '2181', 'h', '8577', 'a', '5027', 'x', 'u', '1039', '347', '8219', 'c', '1063', '8885', 'f', 'd', '3067', '2509', 'i', 's', '5509', '2003', 'h', '8869', 'x', 'd', '5141', 'h', 'i', 'b', 'o']
answer:
a, b, c, d, f, h, i, m, o, s, u, x


question:
['7989', '6897', 'o', 'v', '5687', '2933', 'w', '8207', 'y', 's', 'w', '3013', 'h']
answer:
h, o, s, v, w, y


question:
['p', '8865', 'o', 'r', 'j', '907', 'l', 'j', '2835', '6147', 'q', 'h', 'r', 'x', '1181', '2477', 'b', '3043', '1625', 'w', '1643', 's', '6089', 'w', 'd', '2299', '4405', '7005', '4083', '841', '4235', 's', '5367', 'o', 'd', 'n', 'f']
answer:

b, d, f, h, j, l, n, o, p, q, r, s, w, x