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]: ['8887', '1199', 'r', '7209', 'k', '7567', '7239', 'k', '5123', 'w', '4523', 't', 'd', '5289', '5737', '485', 'w', 't', '7651', 'v', '7213', '7687', 'y', 'w', '7265', 'b', 'b', '3667', 'z', '9935', 'i', 'l', 'u', '6715', 'j', '9815', '8925', '7941', 'w', 'm', '3907', '621', '5523', '5849']
[EX A]: b, d, i, j, k, l, m, r, t, u, v, w, y, z

[EX Q]: ['m', '6761']
[EX A]: m

[EX Q]: ['4563', 's', 'g', '3645', 'l', '489', '8465', 'c', 'p', 'w', 'w', 'm', 'k', '5967', '5891', 'j', 'f', '7175', '585', '531', 'n', '8407', 'w', '9565', '1577', 'z', '5851', '437', 'i', 'a', 'y', 'a', '2405', '4243', '2613', 'v', 'c', '4625', '6581', 'l']
[EX A]:
a, c, f, g, i, j, k, l, m, n, p, s, v, w, y, z