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: ['491', '229', 'g', '6677', '4793', 'h', 'x', 'a', '2333', 'u', 'l', '785', 'p', '7331', '653', '5193', '5415', '8417', 'v']

Output: a, g, h, l, p, u, v, x


Input: Consider Input: ['m', '6761']

Output: m


Input: Consider Input: ['1157', 'x', 'k', '9795', 'n', 'm', 'g', '1265', 'm', 'q', '1791', 'e', '2909', '5785', '5643', 'n']


Output: e, g, k, m, n, q, x