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:
['s', 'c', 'e', '2457', '9413', 'r', '9949', 's', 'z', 'e', 'a', 'o', '7207']

Ex Output:
a, c, e, o, r, s, z


Ex Input:
['2995', '8179', '8131', '5655', 'j', 'q', 'l', '3193', '1823', 'y', 'n', '7645', 's', '5665', 'r']

Ex Output:
j, l, n, q, r, s, y


Ex Input:
['333', 'b', '261', 'k', 'p', '7861']

Ex Output:

b, k, p