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: ['2521', '8027', 'm', '193', '615', 'l', '1947', '5949', '6307', 'r', '1015', '743', 'v', '6949', 'b', 'g', '8841', 'c', 'b', '2879']

Output: b, c, g, l, m, r, v


Input: Consider Input: ['5075', '9169', '4659', '7605']

Output: -1


Input: Consider Input: ['o', 'g', '6475', '3027', 'p', 'v', '3661', 'k', '1693', '4575', 'y', 'k', 'x', 'z', '7141', 'p', 't', 't', 'm', 'd', '2651']


Output: d, g, k, m, o, p, t, v, x, y, z