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: ['357', 'i', '2379', '8835', 'n', '8971', 't', '1879', '1597', '3241', '4271', 'm', 'e', '5465', 'e', '6037', 'r', 'k', 'z', '4999', 'h', 't', 'g', 'g', 'y', 'b', '4765']
A: 
b, e, g, h, i, k, m, n, r, t, y, z