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.

['s', 's', '6581', 'e', '7355', '1315']
e, s

['t', 'a', '2481', '2841', 'a', '2871', 'm', '4435', 'g', '8201', '4351', '9045', 'o']
a, g, m, o, t

['7275', '3949', '5567', 'z', '7631', 'c', '8837', 'r', '7855', 'c', '1897']

c, r, z