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:
['n', 'h', 'j', '5945', '8511', 'y', '7739', '4717', '2483', 'p', '9545', '7647', '9863', '5591', '5393', 'i', '9225', '589', '1497', 'j', 'm', '2397', 'a', 'd']
answer:
a, d, h, i, j, m, n, p, y


question:
['7203', '8715', '3193', 'w', '7159', '8535', 'i', '2425', 'j', 'f', '6709', 'w', 'w', 's', 'e', '9337', 'r', 'r', '5255', '1707', 'u', '1443', 'e', 'e', 'v']
answer:
e, f, i, j, r, s, u, v, w


question:
['6447', '2555', '2445', 'v', 'm', '9813', 'l', 'j', 'f', '279', 'm']
answer:

f, j, l, m, v


