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]: ['6027', 'v', 'b', 'l', '7853', 'r', 'y', '2919', '3831']
[EX A]: b, l, r, v, y

[EX Q]: ['o', 'l', 'm', 't', '4487', '1019', '9903', 'c']
[EX A]: c, l, m, o, t

[EX Q]: ['b', 'e', '5523', 'f', 'm', '4891', '31', 'l', 'q', 'f', '6397', '1815', '9537', '5279', '1837', 'w', 'j', '2479', 'k', 'x', '423', 'e', '6475', 'o', 'g', '99', '6821', 'j', '27', '9565', 'c', 'i', '5015', '5365', 'z']
[EX A]:
b, c, e, f, g, i, j, k, l, m, o, q, w, x, z