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.

['j', '6675', 'u', 's', '705', '8227', 'f', 'w', 'n']
f, j, n, s, u, w

['w', '491', 'x', 'u', 'z', 'q', '5411', '7629', '8261', '8629', '1441', '5139', 's', 'm', '6463', 'u', 'z']
m, q, s, u, w, x, z

['s', 'w', 'c', '4137', 't', '2437', '349', 'h', '4539', 't', 'b', 'y', 'q', 't', '9087', 'c', '9489', '6285', '6247', '8353', 'n', 't', '8661', 'p', 'z', 'p', '773', 'w', 'q', '8081', 'r', 'u', 'z', 'k', 'a', 'b', '7513', '5549', '5325', '1101', 's', '6507', '3317']

a, b, c, h, k, n, p, q, r, s, t, u, w, y, z