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:
['699', 'd', '6027', 'j', 'e', 'c', 't', '9983', '5471', '2649', 't', '2631', 'r', 'h', '293', 'j', '8699', 'p', 'k', '5433']

Ex Output:
c, d, e, h, j, k, p, r, t


Ex Input:
['1707', '381', '3957', '7853', '4987']

Ex Output:
-1


Ex Input:
['u', 'v', '2891', '8355', '8187', 'b', 'w', '5479', 'n', 'y', '6191', '5581', 'y', '5765', '9257', '8395', 'b', 'd', '8389', '8577', 'z', '5789', 'y', 'g', '5171', 'x', 'e', 'i', 'm', '4755', 'm', '3293', '7255', 'k', '6301', '7927', '7849', 'o', 'o', 'a', 'b', '9481', '9843', 'a', '4503']

Ex Output:

a, b, d, e, g, i, k, m, n, o, u, v, w, x, y, z