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.

[EX Q]: ['3395', '7471', 'n', '9537', '1255', '1997', '3085', '4863', '9797', '4275', 'k', 'f', '8973', '3939', 'p', 'q', '4977', '6231', '8745']
[EX A]: f, k, n, p, q

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

[EX Q]: ['993', 'x', 'w', '8263', 'w', 'd', 'b', '3613', '2351', 'c', 'l', '2403', '9963', 'f', 'b', 'g', '1355', '3003', '7939', 'o', '8489', 'v', 'm', '6937', '4603']
[EX A]:
b, c, d, f, g, l, m, o, v, w, x