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:
['9483', '501', 'j', 'k', '3103']
answer:
j, k


question:
['m', '5005', 'y', 'h', 'w', '3609', 'p', '2539', '3307', 'p']
answer:
h, m, p, w, y


question:
['4085', 'd', 'h', 'g', '1957', 'g', 'z', '7699', 'k', 'j', '8243', 'i', '7011', '1265', 'n', 'a', '5859', 'z', '6755', 'h', 'f', '2365', 'w', '1293', '2613', 'x', '673', 'g', 'p', '4307']
answer:

a, d, f, g, h, i, j, k, n, p, w, x, z