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: ['i', '9215', 'n', 'p', '4815', '8757', 'm', '1755', 'c', 'z']

Answer: c, i, m, n, p, z


Question: ['s', 's', '6581', 'e', '7355', '1315']

Answer: e, s


Question: ['h', 'x', 'q', '9467', '8185', '7265', 'd', '6573', 'n', '4633', 'm', 'a', 'r', 's', 't', 'u', 'y', 'j', 's', 'z', 'd', 's', 'z', '4409']

Answer:
a, d, h, j, m, n, q, r, s, t, u, x, y, z