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', '1191', '5581', '2527', 'g', '9795', '519', 'u', '8389', '9793', 'k', '5733', '7125', '7835', 'j', '855', 'd', 'd', '6555', '3211', 'l', 'o', 'b', '523', 'x', 'j', '1707', '4161', '7171', 'h', 'h', 'm', 'h', '2443', 'e', '649', '951', 'n', 'h']
answer:
b, d, e, g, h, i, j, k, l, m, n, o, u, x


question:
['p', '2923', 'e', 'k', '5433', '605', '5079', 'k', 'p', 'x', '4845', '4099', '6795']
answer:
e, k, p, x


question:
['7315', '845', 'f', '7731', 's', 'h', 'l', '7203', 'n', 'b', '5297', 'b', 'd', '2723', '6481', '9477', 'i', '4127', 'z', '9153', 'j', '5185', '8281', 'e', '8111', 'd', '5849', 'x', '8925', '5677', 'h', '7629', 'y', 'g', '1323', '6791', '3111', 'u', 'l', '2813', '2925', '9349', 'r']
answer:

b, d, e, f, g, h, i, j, l, n, r, s, u, x, y, z