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.

['8879', 'x', '1383', '4925', '2867', 'j', 't', 'e', 'w', 'p', 't', 'w', 'l', '7447', '1877', '7747', 'k', 'b', 'x', '8565', 'q', '8575', '5711', '2949', '5637', '2197', '4905']
b, e, j, k, l, p, q, t, w, x

['9013', 'e', 'm', 'p', 'k', '161', 'k']
e, k, m, p

['5751', 's', 'h', 'p', 'c', 'v', '2025', 'z', 'e', 'b', 't', '9279']

b, c, e, h, p, s, t, v, z