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:
['c', '8785', 'u', 'i', 'i', '6513', '6093', 'w', 'i', 'x', '9377', 'p', '1545', '7997', 'a', 'c', '125', 'u', '9149', '9103', 'u', 'o', 'h', '2275', '8503', '3251', 'c', '9925', 'w', '6873', 'c', 'h', 'e', '2369', 'c', 'z', '1337', '9541', '675', 's']
answer:
a, c, e, h, i, o, p, s, u, w, x, z


question:
['7123', 'm', 'h', '4065', 'c', 'n', '187', '3899', 'r', 'k', '2071', '9481', '6277']
answer:
c, h, k, m, n, r


question:
['439', '2651', '4957', 'l', 'j', '7515', 'j']
answer:

j, l