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:
['k', 'c', 'i']
answer:
c, i, k


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:
['2469', '4757', '3251', 's', '3331', 'u', 'x', '1373', '4017', '1493', '1951', 'y', '5843', '6815', 'b', 'q', '6949', 'e', 'n', 'g', '9169', 'y', 'd', 'g', 'f', 'y', '4105', '3225', '9561', 'y', '1085', '9243']
answer:

b, d, e, f, g, n, q, s, u, x, y