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:
['k', 'v', 'e', '6377', 'y', '3585', '4535', 'f', 'g', 'm', 'f', '8369', 'v', '7445', '4527', '9383', 'n']
answer:
e, f, g, k, m, n, v, y


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:
['1409', '8331', 'x', '5681', '1605', 'y', 'd', '4127', '9191', '9851', 'w', 'w', '8331', '1119', '9169', 'q', 'f', 'o', 'o', 'o', '3599', '4815', 'f', '2625', '5257', '8707', 'j', 'h', '3643', '4307', 'g', '6317', 'g', '7983', '1175', '2595', 'k', 'i', 'u']
answer:

d, f, g, h, i, j, k, o, q, u, w, x, y