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]: ['5611', 'x', 't', 'p', '5711', '7079', '5251', '429', 'z', 'u', '8721', '9321', '79', 'i', '189', '3605', 'k', '445', 'r', 'k', 'o', '2189', '8521', '8849', '2651', 'm', '4149', '1577', '3085', '5275', '6413', '5265', '6089', 'r', 'f', '5013']
[EX A]: f, i, k, m, o, p, r, t, u, x, z

[EX Q]: ['b', '7797', '8431', '4413', 'd', 'g', '821', '2223', 'r', 'a', 'y', 'c', '297', 'g', 'y', '6535', '7881', 'd', 'm', '1381', 'u', '4863', 'y', '6197', '3855', 'o', '4199', 'h']
[EX A]:
a, b, c, d, g, h, m, o, r, u, y