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.
--------
Question: ['1063', 'f', 'm', 'i', 'x', 'i', 'd']

Answer: d, f, i, m, x


Question: ['6463', '871', '5781', '283', '9653', 'f', '9661', '3365', '2889', '5499']

Answer: f


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

Answer:
d, f, k, m, r, z