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:
['3127', '9253', '5667', '9453']
answer:
-1


question:
['i', '9575', '8995', 'm', 'o', '3015', '4005', '6909', '7195', '3361', 'j', '5253', '9523', '8879', '5861', 'e', 'y', 'e', '1525', 'i', '807', '8469', '3333', '4017', '2237', '3387', 'o', '643', 'p', '7129', '6243', 'y', '4913', 'z', 'f', '6909', 'f', '4347', '7227', 'o', 's', '9909', '8611']
answer:
e, f, i, j, m, o, p, s, y, z


question:
['b', '8023', '1277', 'm', '6181', '813', '6931', '9741', 'n', 'q', '8605', 'x', '4549', 'w', '2709', '4853', '9101', '313', 'r', 'j', 'c', 't', 'a', 'b', 'l', 's', '351', '1905', '5569', 'd', 'q', 'r', '605']
answer:

a, b, c, d, j, l, m, n, q, r, s, t, w, x