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: ['p', '9641', '8515', '1207', 'd', 'j', '6617', '5529', 'g', 'a', 'o', 'f', 'y', '4993', '4643', '6087', 'n', '3177', 'y', '9471', '1229', '8211', '7079']
Example Output: a, d, f, g, j, n, o, p, y

Example Input: ['7997', 'm']
Example Output: m

Example Input: ['q', '4481', 'n', '2501', 'u', 'f', 'm', 'm', '7961', 'i', '2757', 'a', '2729', '4865', 'f', 's', 's', 'y', 'q', '7933', '459', 'y', 'k', '1185', '1709', 'h', '3391', '4311', '9459']
Example Output:
a, f, h, i, k, m, n, q, s, u, y