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:
['7591', '1403']
answer:
-1


question:
['8301', 'd', 'p', 'l', 'm', '9099', 'o', '8045', 'e', 's', 't', '8853', 'v', '6375', 'q', '2505', 's', '4219', '3587', 'g', '651', '7129']
answer:
d, e, g, l, m, o, p, q, s, t, v


question:
['w', '7289', '3385', '6697', 'h', 'j', '4349', 'e', '1019', '3595', 'k', '1075', '4531', '5691', '8201', '9891', '4349', 'w', 'o', 'f', '8329', 'b', '5479', 'b', 'c', 'q', 'b', 'v', 'u', 'r']
answer:

b, c, e, f, h, j, k, o, q, r, u, v, w