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:
['2349', 'p', 'a', '435', 'y', 'h', '3249', 'o']
answer:
a, h, o, p, y


question:
['s', 'w', '8949', '4025']
answer:
s, w


question:
['g', 'b', '685', 'w', '9263', 'v', 'j', '6501', 'm', 'e', '6487', '2267', 'h', 'y', 'm', 'j', '6001', 'f', '5015', '1781', 'q', '6207', 'q', '3933', '3411', 't', '7913', '2465', '7611', 'h', '5759', '523', 'h', '2377', 'k', 'y']
answer:

b, e, f, g, h, j, k, m, q, t, v, w, y