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:
['u', 'k', 'd', '4393', 'u', 'h', 'q', '833', 'k', 'l', '5749', 'r', '7123', '1003', 'z', '531', 'o', 'u', '6601', '6975', '4905', 'n', 'e']
answer:
d, e, h, k, l, n, o, q, r, u, z


question:
['5431', 'o', 'u', 'l', 'f', 'd', 'r', '1479', '9357', 's', 'v', '6399', 'b', '7937', 't', '8497', 'r', '131', 'h', 'c', 'v', '8879', 'k', 'r', '4687', 'l', '1065', 'r', 'w', 'l', '3305', '461', 'q', 'h', 'b', 'e', 'e', 'w', '5999']
answer:
b, c, d, e, f, h, k, l, o, q, r, s, t, u, v, w


question:
['c', 'u', 'j', '695', '2457', 'f', '9493', 's', '5167', 'w', 'f', 'l', 'o', 'l', '2455', '9127', '997', '9163', 'm', 'f', 'j', '3949', 'n', 'c', 'd', 'd', '4891', 'q', 's', '895', 'l', '4761', 'h', '8625', 'r', '3093', '183', 'w', '4659', 'v', 'o']
answer:

c, d, f, h, j, l, m, n, o, q, r, s, u, v, w