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:
['w', 'g', '1649', 'a', '2115', '6763', 'r', 't', 'l', 's', 'y', '5659', 'a', 'b']
answer:
a, b, g, l, r, s, t, w, y


question:
['m', '8127', '7519', '4543', '2809', '9855', 'n', '6241', 'w', 'w', 'q', 'w', 'p', '8599', '7819', '3817', 'm', 'q']
answer:
m, n, p, q, w


question:
['d', 'h', '9965', 'e', '1797', '639', 'z', '1741', '4795', 'n', '4551']
answer:

d, e, h, n, z