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.

Ex Input:
['477', '3931', 'g', '5967', 'm', '9845', '1607', 'a', '1749', 'k', 'j', '7945', '9125', 'v', 'n', 's', '5185', '1117', '17', 'x', '4149']

Ex Output:
a, g, j, k, m, n, s, v, x


Ex Input:
['n', 't', '2901', '9697', 'a', 'j', 'x', 'a', '4437', '2255', '2177', 's', '3173', 'j', 't', '5713', '4091', '4253', '5553', 'i', '4533', 'i', 'e', '6899', 's', '3541', '2139', '2705', 'm', 'u']

Ex Output:
a, e, i, j, m, n, s, t, u, x


Ex Input:
['l', '2131', 'n', '387', '5487', 'u', '5617', 'r', 'j', 'x', 'd', 'e', '6339', 'n', 't', '8623', 't', '3089', 'h', 'd', '8247', 'f', '9119', 'd', 'h', 'f', '3201', '7195', 'n', 'h', '9505', 'h']

Ex Output:

d, e, f, h, j, l, n, r, t, u, x