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:
['e', 'n', 'y', 'f', 'l', 'h', '455', 'y', '591', 'm', '9041', 'b', 'b', 'o', '4215', '5009', 'o', 'a', '4369', 'u', '6911', '4825', 't', 'k', '6063', '2939']
answer:
a, b, e, f, h, k, l, m, n, o, t, u, y


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:
['1991', 'b', '8165', 'f', 'k', 'g', '985', '5271', '1845', '261', 'r', 'g', 'p', '5417', '697', 'a', 'l', '3839', '1665', 'q', '7207', 'r', '3285', '129', '2213', 'f', 'f', 'u', 'c', 'm', 'v', '4603', 'n', 'n', '3525']
answer:

a, b, c, f, g, k, l, m, n, p, q, r, u, v


