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.

['4299', '8125', 'z', '6931', '5643', 'z', 'k', '5963', 'x', '9899', '1139', '819', '589', '4479', '5177', '7887', '6465', '2909', 'l', 'q', 'z', '2313', 'u', '2517', '9075', '7441', 'x', 'x', '5489', '6377', 'q', '4671', '7171', 'r', '6879', '9517', 'a', '3259', 'z', 'i', '7941', 'p', '6341', '2031', 'c']
a, c, i, k, l, p, q, r, u, x, z