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.

['1979', 'b', 't', '1101', '7953', '2451', '7539', '6833', 'u', '49']
b, t, u

['w', '5341', 'b', '6243', 'v', '877', '1087', '6763', '5241', '3369', '9119', 't', 'v', 'j', '8261', 'o', 'b']
b, j, o, t, v, w

['7549', '6769', '7343', '9907', '9067', 'm', '8167', 'c', '4343', 'r', 'm', 'q', '5477', '3033', '9479', 'e', 'u', 'g', 'v', '701', 'u', 'f', '169', 'l', 'k', '5531', 'k', 'f']

c, e, f, g, k, l, m, q, r, u, v