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', 'g', '4563', 'v', 'm', '107']
answer:
g, h, m, v


question:
['d', 'o', '7643', '9065']
answer:
d, o


question:
['y', '3247', '6053', 'b', 'c', 'n', '9339', '67', '341', 'h', '269', 'k', 'z', '3969', 'e', 'z', 'g', 'i', 't', '3303', '3243', 'q', 'y', 'i', '6595', '459', '6547', '7143', '5391', 't', '8245']
answer:

b, c, e, g, h, i, k, n, q, t, y, z