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:
['z', 'm', 'n', 'u', '9159', '7931', '5401', '1383', '8195', 't', 'x', 'q', 'r', '2535', 's', 'j', 'c', '8123', '2429', '5581', 'k', 'c', 't', 'i', 'm', 'o', 't', 'q', '4819', 't', '1649', 'r', 'y', 'z', '8813', '7451', '199', 'o', 'x', 's', 's', '6747']

Ex Output:
c, i, j, k, m, n, o, q, r, s, t, u, x, y, z


Ex Input:
['o', '1099', 'r', '8995', 'o', '2909']

Ex Output:
o, r


Ex Input:
['7815', 'r', 'r', 'a', 'a', '819', 'i', 'n']

Ex Output:

a, i, n, r