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.

[Q]: ['9117', '1153', 'f', 'b', '9979']
[A]: b, f


[Q]: ['c', '7039', 'g', '1899', 'r', '507', 'c', '2587', '3865', '1729', '3927', 'r', '3535', '2791', 'm', 'l', 'r']
[A]: c, g, l, m, r


[Q]: ['167', 'i', 'c', 'j', 'g', '9823', 's', 'w', '411', 'r', 'z', '1737', 'n', 'd']
[A]:
c, d, g, i, j, n, r, s, w, z