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.

Input: Consider Input: ['3395', '7471', 'n', '9537', '1255', '1997', '3085', '4863', '9797', '4275', 'k', 'f', '8973', '3939', 'p', 'q', '4977', '6231', '8745']

Output: f, k, n, p, q


Input: Consider Input: ['8489', 'h']

Output: h


Input: Consider Input: ['x', '1277', 'h', 'n', 't', '7471', '7695', 'w', 's', 'c', 'h', 'x', '1743', 's', '3489', 'w', 'x', 'u', '8187', '339', '807', '4059', 'z', 'b']


Output: b, c, h, n, s, t, u, w, x, z