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]: ['l', 'i']
[A]: i, l


[Q]: ['8051', 'h', 'g', 's', 't', 'p', 'w', 'x', 's', '8521', 'm', '9719', 'j', 'n', 'i']
[A]: g, h, i, j, m, n, p, s, t, w, x


[Q]: ['p', 'c', '8153', '4369', '5663', 'w', '2279', 'y', '9815']
[A]:
c, p, w, y