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.

Example Input: ['5971', 'x', 'c']
Example Output: c, x

Example Input: ['7777', '6223', 'k', 'k', 'd', '9743', '189', '7705', 'c', '6115', '4275']
Example Output: c, d, k

Example Input: ['5005', 's', 'p', 'o', '4727', '8263', 'w', '5561', '4735', 'g', 'f', 'o', 'w', '1665', '8197', '163', 'p', 'b', '3967', '3917', 'd']
Example Output:
b, d, f, g, o, p, s, w