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', 'x', 'n', 'w', '8915', 'd', 'd', 'd', '6025', '7861']

Ex Output:
d, i, n, w, x


Ex Input:
['231', 'r', '5673', 'j', '589', 'z', '4659', 'a', '3763']

Ex Output:
a, j, r, z


Ex Input:
['t', 'i', 'd', 'e', 'e', 'w', '6955', '393', 'e', '2783', 't', 'g', 'c', 'g', 'r', 'k', '103', '4417', 'h', 'g', '1699', 'c', 'g', 'k']

Ex Output:

c, d, e, g, h, i, k, r, t, w