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:
['3035', 'f', 'k', 'e', '3023', 'p', '9667', '5277', '4757', '8433', 'g', '1399', '7721', 'n', 'p', '7469', '7581', '5679', 'g', 'q']
answer:
e, f, g, k, n, p, q


question:
['9263', '7849', '4491', 'q', '1187', '455', '6575', 'c', 'o', '9125', 'b', 's', 'y', '5305', 'q', 'j', 'z', '5301', '4757', 'u', '3317', '7609', '8729', 'f', '2863', 'n', '6155', '9959', 'r', 'p', '3267', '7891', 'v', 'a', '6093', 'u', 'y', 'e', 'v', 'l', '4075', 'e', 'e']
answer:

a, b, c, e, f, j, l, n, o, p, q, r, s, u, v, y, z