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:
['h', '1797', '8211', 'n', 'r', '7707', '2063', '4655', 'x', '5521', '8327', 'g', '7659', 'i', 'x', 'w', '9465', '4625', 'q', '5377', 'r', '225', 'r', 'i', 'e', '4163', 'g', 'g', '3537', 's']
answer:
e, g, h, i, n, q, r, s, w, x


question:
['1593', '8165', 'q', '6689', 'b', 'r', '373', 'g', '6505', '415', '495', 'j', 'j', 'f']
answer:
b, f, g, j, q, r


question:
['3279', 'f', '6671', 'w', '1745', 'c', 'x', 'a', '2923', '2211', '6553', '5043', 'w', '5353', '2009', '2935', 'r']
answer:

a, c, f, r, w, x