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:
['9925', 'f', '6149', 's', 'd', 's', '75', '8577', '2319', 'b', '3769', '5211', 'q', 'm', '8127', 'f', '3801']
answer:
b, d, f, m, q, s


question:
['e', '8391', '7065', '6141', '3335', 't', 'i', 'c', '1791', '6333', 'b', 'z', '1621', 'e', 'h', 'u', 'o', 'q', '3195', '6507', '3253', 'c', '2067', '3917', '7111', 'r', 'j', 'd', '3987', '9139', 'm', '981', 'l', 'f', '2417', 'w', '9983', 'h', 'd', '6021', 'a', 'f']
answer:
a, b, c, d, e, f, h, i, j, l, m, o, q, r, t, u, w, z


question:
['8461', '769', 'o', 'o', '6693', '7143', 'm', 'z', '4957', '9913', '2239', '11', 't', '3291', 'k', '6891', '8597', '5863', 'd', '5529', '385', 'f', 'x', '9525', '8425', 'x', 'b', 'h', '1125', '4109', 'f', 'z', 'q']
answer:

b, d, f, h, k, m, o, q, t, x, z