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.

Ex Input:
['3743', '765', '5299', '3069', '8547', '8991', '1811', 'k', '5557', '4907', '5907', 'd', 'r', 'z', '5385', '5463', 'f', '2063', 'm', '3419', 'k', '3897', '4049']

Ex Output:
d, f, k, m, r, z


Ex Input:
['d', 'o', '7643', '9065']

Ex Output:
d, o


Ex Input:
['4201', '785']

Ex Output:

-1