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:
['5973', 'h', '4081', 'i', '8059', 'w', 'j', '6175', 'w', '8685', '5811', 'k', 'n', '5577', '9817', 'v', '8617', 'u', 'y', '3921', 'b', '1027', '5405', 'a', '3501', '6659', 's', 'e', '157']
answer:
a, b, e, h, i, j, k, n, s, u, v, w, y


question:
['a', 'y', '7401', 'e', 'l', '4351', 'p', '5673', 'k', '333', 'o', 'd', 'e', 'j', 'e', '9569', '1795', 'r', 'z', '6059', '4399', '2927', 'n', '9387', '9317', 'b', 'c', 'e']
answer:
a, b, c, d, e, j, k, l, n, o, p, r, y, z


question:
['561', 'p', '5831', 'd', '9091', '739', 'b', '2379', '5603']
answer:

b, d, p