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]: ['6143', 'y', '5505', '9813', 'r', 'v', 'u', '8681', '2387', 'u', 'o', 'm', '9793', 'm']
[EX A]: m, o, r, u, v, y

[EX Q]: ['r', 'q', '3649', 't', '3941', 'z', '3729', 's', 'g', '6905', 'h', 'v', '1085', '6353', 'a', '9395', '5433', 'a', '2565', 'p', 'a', 'h', '1491', 'j', 'b', 'v', 'e']
[EX A]: a, b, e, g, h, j, p, q, r, s, t, v, z

[EX Q]: ['9651', 'd', 'o', '6393', 'g', '743', 'g', 'c', '565', 'c', 't', 'm', '6271', '2459', 'm', 'b', 'l', 't', '1921', '2089', 'a', 'q', 'o', '5477', 'd', 'm', '9139', '1003', '2919', 'l', 's', 'c', 'j']
[EX A]:
a, b, c, d, g, j, l, m, o, q, s, t