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:
['887', 'p', '3819', '2727', '1407', 'b', 'n', '737', 'd', 'w', 'q', '6877']

Ex Output:
b, d, n, p, q, w


Ex Input:
['e', 'k', '7569', '6387', '4593', '2445', '345', '2905', 'h', '3119', '7001', 'x', 'a', '2943', '3635', 'l', 'q', 'z', 'g', '2657', '7849', 'i', '9413', 'm', 'e', '2951', 'd', '2963', 'b', 'u', 't', 'i', '1141', 'c', 'm', '8607', 's']

Ex Output:
a, b, c, d, e, g, h, i, k, l, m, q, s, t, u, x, z


Ex Input:
['k', 'r', 'b', '2323', '6131', '7801', 't', '8657', 'v', '2651', '5129', 'q', '7449', 't', '5611', '2501']

Ex Output:

b, k, q, r, t, v