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:
['f', 't', '2135', '8397', '6361', '389', '2253', 'x', 'p', '4833', '5785', 'x', '1811', '9639', '5739', '175', '3231', '5931', 'r', 'c', 'g', 'h', 'p', '909', 'p', '587', 'a', 'a', 'h', 'q', 's', '5945', '4911', 't', 'h', '7517', 'p', '3177', 'h', 'u', '3577', '7055', 'l']
answer:
a, c, f, g, h, l, p, q, r, s, t, u, x


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:
['o', '1637', 'o', 'x', 'm', '8349', 'n', 'o', 'e', '6381', '5345', '9355', 'r', 'm', 't', '4789', 'i', '4741', '5577', 'k', '113', 'i', 'y', 'i', 't', 's', '5321', 'n', 'o', 'g', '7755', '6503', 'o', 'b', '1983', 'k', '333', '4091', 'h', '4535', 'r']
answer:

b, e, g, h, i, k, m, n, o, r, s, t, x, y