instruction:
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.
question:
['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']
answer:
e, f, l, n, p, q, r, s, w, y


question:
['g', '6867', '7965', '3313', 'k', '1827', '7337', 'u', '1209', '5145', 'w', 'h', '9059', 'u', 'b', '3189', '2837', 'k', 'y', 'e', 'b', '4479', '541', '7103', 'h', 'm', '2177', '6377', '3993', '7167', 'q', '2145', '5007', '9135', '5331', 'e']
answer:
b, e, g, h, k, m, q, u, w, y


question:
['9747', '8827', 'x', 'r', '3005', 'o', 'i', 's', '5293', 'a', 'b', 'z', '4719', 'o', '3413', 'w', '6241', '3729', 'i', '5915', '6145', 'f', '4953', '9445', 'p', 'x', '8989', '7197', 'h', '5941', '9633', 'p', '1479', '4087', 'p', 'm', '2365', 'y', 'e', 't', 's']
answer:

a, b, e, f, h, i, m, o, p, r, s, t, w, x, y, z