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:
['p', '2923', 'e', 'k', '5433', '605', '5079', 'k', 'p', 'x', '4845', '4099', '6795']

Ex Output:
e, k, p, 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:
['c', 'l', '9161', '7709', '3539', '1691', 'f', 'i', '1463', '365', '3995', 'o', '1309', '7509', '3711', '3891', 'r', '4583', '667', 'n', '7353', 'j', '9479', 'd', '3459', '4027', '5961', 'c', 'v', '7753', 'p', 'e', 'd', 'c', 'e', '7101', '2303', '6265', 't', 's', '7521', 'h', '5477', '9083', '3331']

Ex Output:

c, d, e, f, h, i, j, l, n, o, p, r, s, t, v