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: ['895', '2049', '8839', '1773', 'v', '467']
Example Output: v

Example Input: ['8783', '1505', 's', '7675', 'g', '4749', '7997', '3753', '6277', '1025', '5595', 'l', 'i', 'm', '8557', '9457', 'h', 'n', '625', 'f', 'a', '9731', '4853', 'a', '7669', '8507', '4423', 's', 'a', 'k', 'm', 'u', 'p', '4641', 'j']
Example Output:
a, f, g, h, i, j, k, l, m, n, p, s, u