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: ['s', 'u']

Answer: s, u


Question: ['j', 'r', 'z', 'f', '1485', '2419', 't', 'd', '6023']

Answer: d, f, j, r, t, z


Question: ['9555', '5983', '1853', 'c', 'z', 't', 'p', '9041', 'd', '5919', '1621', '345', 's', '2647', '4261', '8611', 'w', 'x', 'p', '9103', '2599', '5101', '9261', 'k', '7437']

Answer:
c, d, k, p, s, t, w, x, z