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:
['q', 'h', 'q', '7185', 'f', 'l', 'r', '3605', 'x', 'i', 'v', '8789', 'u', 'x', 'x', '8315', 'x', 't', 'h', 'o', '4943', '5827', '7677']
answer:
f, h, i, l, o, q, r, t, u, v, x


question:
['7823', '2933', 'k', '4139', '5585', 'f', 'c', 'm', '2035', 'q', 'z', 'l', '1999', 'q', 'p', '7291', '2091', 'v', '423', 'e', 's', '6089', '4763', '6739']
answer:
c, e, f, k, l, m, p, q, s, v, z


question:
['3185', 'g', 'h', 't', 'u', '8623', '5673', '8323', 'e', '2917', '1931', '4759', '351', '5197', '7993', 'b', 'w', '5969', 'h', 'f', '8391', '7037', '875', '5839', '3409', '8645', '6287', 'x']
answer:

b, e, f, g, h, t, u, w, x