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:
['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:
['5011', 'l', '925', 'e', 'b', '3077', 'm', '4541', '781']
answer:
b, e, l, m


question:
['4067', 'j', 'q', '1995', 'q', 'v', '4863', 'd', 'm', '1971', '7303', 'd', '6969', '6731', 'w', '5243', 'p', 'o', 'c', '3723', '2595', '1327', 'i', '6529', 'u', '3653', '2355', 'u', 'h', 'o', '3363', '3591', 'r']
answer:

c, d, h, i, j, m, o, p, q, r, u, v, w