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]: ['j', '917', 'w', 't', '8873', '1431', '8059', '7041']
[EX A]: j, t, w

[EX Q]: ['4641', '2881', 'c', '4827']
[EX A]: c

[EX Q]: ['j', 'a', 'h', '3579', 'n', '9747', 'd', 'e', 'x', 'm', 'f', 'b', '6689', '9303', 'y', '8073', '2975', 'i', 'v', '7389', '3529', 'w', 'l', '9645', 'x', '1135', 'm', '7391', 'o', '4757', '2885', '7489', '6315', 'e', '9667', 'z', '3019', 'g', '1647', 'd', 'w', 'c']
[EX A]:
a, b, c, d, e, f, g, h, i, j, l, m, n, o, v, w, x, y, z