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:
['c', 'e', '6509', '1295', 'u', '5445', '1731', '3049']

Ex Output:
c, e, u


Ex Input:
['9025', '3259', '4863', 'u', '6443', '9931', '627', 'x']

Ex Output:
u, x


Ex Input:
['6917', 'i', 'v', 'i', '1825', 'v', 'e', '8767', 'p', '2675', '595', 'n', '5681', 'f', 'm', '4933', 's', 'm', '989', '6305', 'b', '1059', '7727', '6247', 'x', 'f', '9715', 'l', 'u', 'u', '6039', '5843', '549', 'm', 'x', '5111', '5933']

Ex Output:

b, e, f, i, l, m, n, p, s, u, v, x