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:
['p', 'v', '1099', 'y', '1313', 's', '181', 'u', 'e', 'u', '8435', '4125', '8661', 'c', '4605', 'f', 'x']
answer:
c, e, f, p, s, u, v, x, y


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:
['u', '1231', '45', '7999', 'l', 'e', 'o', 'y', '6479', '8513', 'k', '1905']
answer:

e, k, l, o, u, y