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: ['4685', '1891', 'u', '9753', 't', '5827', '3987', 'k', 'f', '5557', '453', 'a', 'g', '253', '1905', '9613', '6683', '4311', 'a', 'p', 'e', '2287']
A: 
a, e, f, g, k, p, t, u