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', '6615', 'r', 'q', '3803', '4641', '9775', '7719', 'n', '6571', '2723', '6919', 'e', 'f', '1919', '6963', '2581', 'y', '713', 'w', 'w', 'w', 'l', 's', '3993', '9563', '9365', '9277', '103', '2737', 'y', '6005', '9763', 'p', '261']

Ex Output:
e, f, l, n, p, q, r, s, w, y


Ex Input:
['1449', 'a', '6261', '303', '4651', 'n', 'u', '1595']

Ex Output:
a, n, u


Ex Input:
['c', 'd', 'r', 't', '1693', 'd', '3291', '4789', 't', 'e', 'z', '9977', 'l', 'f', '765', 'j', 'k', '4521', '7903', '9587', '2227', '1807', 'q', '8637']

Ex Output:

c, d, e, f, j, k, l, q, r, t, z