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]: ['6769', '1057', '1021', 'n', '8231', '9173', '8123', 'a', '6053', 'q', 'y', '883', 'r', '1215', 'x', 'o', '9531']
[EX A]: a, n, o, q, r, x, y

[EX Q]: ['x', 'j', '9747', 'i', '2015', '3505', 'q', 'n', 'h', '3011', 'u', '8043', 'j', 'f', 'd', 'a', 'p', '5817', 'l', 'q', '2275', 'n', '7085', '5373', 'l', 'g', 'b', '8043', '3085']
[EX A]: a, b, d, f, g, h, i, j, l, n, p, q, u, x

[EX Q]: ['4393', '6057', 'g', 'k', 'd', 'u', '5975', '8759', 'e', '8421', '7175', 'n', 'e', 'p', 'c', 'y', 'b', '7297', '2499', 't', '7899', 'x', '7731', '9423', '4217', '3315', 'e', 'n', 'm', 'r', 'c', 'q', 'e', 'w', '8759', 'p', '1887', '7137', '9061', '359', '321', 'd', 'n', '8643', '3909']
[EX A]:
b, c, d, e, g, k, m, n, p, q, r, t, u, w, x, y