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:
['g', 'p', '2925', 'n', 'o', 'y', '6381', 'l', '4963', 'g', 'm', 'u', 't', '9389', '3787', '7713', '1251', '779', 'i', 'w', '9869', 'y', 'y', '3881', 'k', 't']
answer:
g, i, k, l, m, n, o, p, t, u, w, y


question:
['m', '3809', 'l', 'k', '1929', '7963', 'n', 'u', '2125', 'g', 'o', '8325', 'o', 'h', 'y', '3025', 'e', 'e', 'c', 'x', '8445', '4979', 'z', 'f', '4201', '4765', 'g']
answer:
c, e, f, g, h, k, l, m, n, o, u, x, y, z


question:
['3835', 's', 'r', '6909', '8099', '379', 'e', 'y', '9557', 'i', '197', 'o', 'r', '7275', 'z', 'n', 'o', 'u', 'y', '5963', '6429', 'h', 'd', 'm', 'k', 'c', '1471', '6947', '5591', '183', 'z', 'w', 'p']
answer:

c, d, e, h, i, k, m, n, o, p, r, s, u, w, y, z