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:
['o', 'h', 'z', 'n', 'e', 'y', 't', '4371', 'm', '1059', '4853', '8529', 'l']
answer:
e, h, l, m, n, o, t, y, z


question:
['135', 'u', '3435', '2985', '9811', 'y', '4309', '9757', '905', 'd', 'g', 'q', '1457', 'l', 'o', 'u', '4517', '2333', '3327', '577', 'a', '4041', '8101', '6211', 'f', 'j', '1721', '7217', 'q', '7443', '8477', '3117', '7779', '9339', '8615', 'm', 'c', 'f', 'c', '8979', '7895', 'k', 'w', '1619']
answer:
a, c, d, f, g, j, k, l, m, o, q, u, w, y


question:
['e', '2257', 'v', 't', '2093', '6129', 'b', 'a', '3287', 'g', 'r', '3287', '197', '7793', 'r', '8057', '6851', '6207', 'q', 'c', '2081', 'y', '6287', '509', '1741', '1173', '1627', '869', '9227', '7521', 'a', '9231', 'n', 'l', '5807', 'n', 'g', 'h', 'b']
answer:

a, b, c, e, g, h, l, n, q, r, t, v, y