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.

Input: Consider Input: ['1707', '381', '3957', '7853', '4987']

Output: -1


Input: Consider Input: ['2915', '6033', '5541', '4685', '1263', '6701', 's', '7269', 'g', '8033', '8171', '6917', 'l', '2913', '447', 'g', 'a', 'z', 'o', '7563', '5385', '5259', '5067', '4869', '2653', '6925', '7001', '8553', 'x', '1243', '9131', '5037']

Output: a, g, l, o, s, x, z


Input: Consider Input: ['g', 'x', 'u', 'u']


Output: g, u, x