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]: ['y', 'b', 'r', 'f', '3745', 'n', '2921', '8133', 'r']
[EX A]: b, f, n, r, y

[EX Q]: ['9483', '501', 'j', 'k', '3103']
[EX A]: j, k

[EX Q]: ['2447', '2373', '8871', '5513', '1907', 's', 'l', 'i', '3889', 'c', 'g', 'z', '6729', 'z', '1193', 'f', '7263', 'b', '2793', '2649', '1635', 'c', 'l', 'k', '8459', '6385', 'e', '9297']
[EX A]:
b, c, e, f, g, i, k, l, s, z