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: ['s', 'u']

Output: s, u


Input: Consider Input: ['8879', 'x', '1383', '4925', '2867', 'j', 't', 'e', 'w', 'p', 't', 'w', 'l', '7447', '1877', '7747', 'k', 'b', 'x', '8565', 'q', '8575', '5711', '2949', '5637', '2197', '4905']

Output: b, e, j, k, l, p, q, t, w, x


Input: Consider Input: ['5473', '2589', 'f', 'l', 'i', 't', '2945', '871', 't', 'l', 'p', 's', '4607', 'r', 'g', '6479', 'c', '2573', 'y', 'a', 'y', '3831', 'k']


Output: a, c, f, g, i, k, l, p, r, s, t, y