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: ['b', 'd', '8153', 'u', '3695', '5317']

Output: b, d, u


Input: Consider Input: ['r', '9489', 'e', 'n', '6323', 'd', '3163', '265', '8587', '7891']

Output: d, e, n, r


Input: Consider Input: ['f', '2879', '8053', '7503']


Output: f