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]: ['1983', '1835', '6543', '6399', '4177', '9385', '7127', 'p', 'l', 'u', 'g', 't', '3423', 'g', 'b', 'l', '3133', '2429']
[EX A]: b, g, l, p, t, u

[EX Q]: ['a', 'y', '7401', 'e', 'l', '4351', 'p', '5673', 'k', '333', 'o', 'd', 'e', 'j', 'e', '9569', '1795', 'r', 'z', '6059', '4399', '2927', 'n', '9387', '9317', 'b', 'c', 'e']
[EX A]: a, b, c, d, e, j, k, l, n, o, p, r, y, z

[EX Q]: ['8835', 'i', 'z', 'u', '7755', '7325', 'n', 'q', 'o', 'k', '4269', 'x']
[EX A]:
i, k, n, o, q, u, x, z