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:
['4743', '9687', '2887', '4413', 'r', 'w', '2355', 'l', 'd', '453', 'o', 'm', '4351', '5881', '3963', 'g', 'r', 'z', 'q', '7555', 'y', '9555', '405', 'n', 'l', '6733', '1763', 'v', '9925', 'y', '633', '827', 'w']
answer:
d, g, l, m, n, o, q, r, v, w, y, z


question:
['2409', 'q', 'w', 'e', 'x', '4737', 'w']
answer:
e, q, w, x


question:
['b', 'y', 'l', '9927', 't', '9259']
answer:

b, l, t, y