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:
['u', '9249', 'u', 't', 'm', 'm', 'n', 'w', '8617', '2729', 'i', 'l', '2971', '3227', 'b', '9017', '4711', 'i', 't', 'r', 'a', 'a', '1701', '6397', '4535', '9167', '6039', '6111', '849', 'p', '8197', '2645', '5147', 'u', 'l', '7419', 'w', 'w', 'k', 'x', 'c', '3377', '4015', '1297', 'f']

Ex Output:
a, b, c, f, i, k, l, m, n, p, r, t, u, w, x


Ex Input:
['4009', 'y', '9077', 'p', 'q', '6711', '6443', '5491']

Ex Output:
p, q, y


Ex Input:
['e', '8017', 'j', '2413', 'f', 'a', 'w', 'b', 'h', '9873', 'k', 'x']

Ex Output:

a, b, e, f, h, j, k, w, x