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:
['w', '6291', '3939', '9569', 'u', '1635', '3359', '8335', 'n', '2799', '7359', 'k', 'm', '2817']

Ex Output:
k, m, n, u, w


Ex Input:
['1979', 'b', 't', '1101', '7953', '2451', '7539', '6833', 'u', '49']

Ex Output:
b, t, u


Ex Input:
['n', '8369', '9069', '2723', 'j', 'c', '3909', 'h', 'w', 'u', '9337', '1343', 'o', '8467', '389', '5157', 'm', 'c', 'c', 'q', 'm', 'f', 't', 'e', 'b', 'i', '5595', '1241', '8813', 'v', 'p', '9079', 'w', 'h', 'y', '9377', 'v']

Ex Output:

b, c, e, f, h, i, j, m, n, o, p, q, t, u, v, w, y