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]: ['3947', '4809', 'b', 'a', '4769', '4179', '535', '5965', 'f', 'j', '2265', 'w', '3103', 'u']
[EX A]: a, b, f, j, u, w

[EX Q]: ['y', '8115', 'f', '5333', 'f', '3437', 'b', 'e', '5719', 'm', 'w', '95', '4863', 'k', '4895', 'a', '8179', 'm', '7919', '1731', '229', 'r', '1847', '7559', '6669']
[EX A]: a, b, e, f, k, m, r, w, y

[EX Q]: ['7125', 't', 'u', 's', '7393', 'c', 'v', 'd']
[EX A]:
c, d, s, t, u, v