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:
['815', '6967', '6553', 'r', 'y', '3641', 'q', 'b', '6131', '4289', 'w', '6093', '6055', 'i', 'b', 'y', '5107', 'v', 'g', '9709', 'x', 'i']

Ex Output:
b, g, i, q, r, v, w, x, y


Ex Input:
['7155', 'y', '145', '7147', 'u', '8453', 'd', '3693', '6471', '5289', 'n', 'p', '8289', '2929', '199', 'e', '8377', '8937', '5315', 't', 'l', '7715', 'c', 'y', 'f', '9999', 'p', '3655', '5489', 'q', '2321', '9881', '2265', 'n', 'v', '455']

Ex Output:
c, d, e, f, l, n, p, q, t, u, v, y


Ex Input:
['a', '3339', '4607', '9171', '9843', '8431', 'o', 'm', '7629', '8023', 'o', '3691', 'f', 's', 'c', 'w', 'y', '4469', 'e', 'n', 'i', 'h', '8443', 'm', '1657']

Ex Output:

a, c, e, f, h, i, m, n, o, s, w, y