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:
['7677', '4069', 'b', 'w', '4381', 'b', '5757', '711', '765', '8347', '6547', '9527', '945', '5333']
answer:
b, w


question:
['5499', 'm', '327', 'h', '5765', '4231', 'y', 'g', 's', '883', '9843', '2751', '8967', 'z', '2301', 'l', 'l', 'k', '7843', '7221', '3643', 'k', '5951', 'r', '9441', '235', '3835', 'l', 'e', 'y', '4061', 'l', '1177']
answer:
e, g, h, k, l, m, r, s, y, z


question:
['h', 'h', '7181', '1405', '5003', 'm', 'p', 'w', '4123', '6907', '8091', '5089', '7517', '183', '213']
answer:

h, m, p, w