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:
['x', '4283', 'n', 'b', 'g', 'p', '8305', '7781', '5907', 's', '1305', 'w', '8623', 'o', 'c', 'u', '1839', '2869', '7537', 'y', '2395', '5309', 'e', '4059', 'l', '6647', 'p', '9717', 'y', 'y', '3769', '2527', '2981', '5255', '4063', 'j', '4843', 'j', '9355', 'z']
answer:
b, c, e, g, j, l, n, o, p, s, u, w, x, y, z


question:
['2943', 'k', '8519', '9103', 'j', '2461', '1049', '2211', '8761', 'l', 'e', '8939', '6013', 'r', '9089', '5781', '5383', '5495', '6699', '7307', '2733', '933', '9865', 'g', '6471', '3179', 'm', '8231', 't', 'e', 'u', '9909', 'g', 'g', '9431', '6521', 'y', 'g', '1415', 'e']
answer:
e, g, j, k, l, m, r, t, u, y


question:
['9491', '7917', 'i', 'r', '2677', 'y', 'n', '1633', '1569', 'u', 'z', '5131', 'f', 'x', 'm', 'i', 'p', 'j', '2393', 'w', 's', '1197', 'l', 't', 'u', 'l', 'f', '15', 'r', '1811', '6977', 'h']
answer:

f, h, i, j, l, m, n, p, r, s, t, u, w, x, y, z