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:
['i', '9215', 'n', 'p', '4815', '8757', 'm', '1755', 'c', 'z']

Ex Output:
c, i, m, n, p, z


Ex Input:
['a', '7599', 'i', '9455', '3955', '2015', 'j', '7345', 'x', 't', 'c', '1317', '9155', '6383', '7793', 'n', '5581', 'v', '3485', 'n', 'r']

Ex Output:
a, c, i, j, n, r, t, v, x


Ex Input:
['161', 'h', '515', '1933', '5823', '8983', 'i', '1583', 'w', 'n', 'i', 'm', 'd', 'n', 'p', '867', '2385', '7519', '6961', 'w', '3483', '7043', 'd', '4397', 'w', 'r', 'p', '203', '639', 'd', '1437', 'd', 'e', 'n', 'g', '3941', '6807', '8867', 'b', '4041', '7807', 'x', 'x']

Ex Output:

b, d, e, g, h, i, m, n, p, r, w, x