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: ['w', '1367', '5389', '9515']

Output: w


Input: Consider Input: ['r', 's', '3409', 'a', 'e', '6855', 'i', 'n', '8655', 's', 't', '8401', 'u', '9603', '8815', 'q', 'a', 'x', 'i', '8455', 'e', '5877', '3917', 'p']

Output: a, e, i, n, p, q, r, s, t, u, x


Input: Consider Input: ['i', '639', 'x', '5545', 'n', 'x', '8859', 't', '845', '4243', '5727', '8463', 'g', '6011', 'g', '1281', 'f', '2025', 'j', '9975', 'c', 'n', 'l']


Output: c, f, g, i, j, l, n, t, x