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: ['t', 'x', '1699', '8727']

A: t, x
****
Q: ['j', '917', 'w', 't', '8873', '1431', '8059', '7041']

A: j, t, w
****
Q: ['u', 'z', '2821', '4633']

A:
u, z
****