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:
['n', '9571', '2983', '7597', 'v', 'y', '1993', '1403', '8309', '7043', 'c', '7329', 'p', '4479', 'p']

Ex Output:
c, n, p, v, y


Ex Input:
['6709', 't', 'n', 'k', '991', 'a', '8899', '3563', '527', 'm', '4599', '6679', 'm', 'x', 'f', 'o', '3275', 'x', '677', 'b', '3329', '3593', '5183', '5753', 'u', '6045', '2607', 'y', '9873']

Ex Output:
a, b, f, k, m, n, o, t, u, x, y


Ex Input:
['u', '2009', 'z', 'i', '3935', '3329', 'g', 'i', '9169', 'b', '3969', '2215', 'h', 'y', 'f', '5791', '8971', 't', 'j', '313', '1449', 'f', 'm', 'n', 'm', '1609', '159', 'o', 'c', '4473', 'w', '4389', 'u', '7301', 'r', '1927', 'd', 'k', '7935', '6487', '1555', 'd', '6079', '4881']

Ex Output:

b, c, d, f, g, h, i, j, k, m, n, o, r, t, u, w, y, z