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:
['h', 'u', 'y', '7677', '9441', '1769', 'v', '1433', 'l', '7739', 'a', '8305', 'n', 'a', '6711', '3161', 'e', 'u', '993', '2211', '4011', 'q', 'o']
answer:
a, e, h, l, n, o, q, u, v, y


question:
['1627', 'r', '2429', 'b', '4451', 's', 'k', 'm', '269', 'l', '709', 's', 'q', '985', 'x', 'j', 'k', 'k', '6603', 'v', '9497', '477', '5803', 'c', 't', 'f', '3189', '6419', '8561', '5709', 'u', 'z', '5717', '9711', 'w', 'y', 'm', 'v']
answer:
b, c, f, j, k, l, m, q, r, s, t, u, v, w, x, y, z


question:
['d', '4481', 'r', '9885', '8035', '4825', '4725', 'w', '9327', '5477', 'y', 'w', '8237', '8035', 'z', '5743', 'z', '1763', 'd', '7671', '5691', 'h', '7967', 'a', '5677', '6751', 'p', 'e', 'g', 'd', 'p', '8793', '2815', '4965', '9541', '4915', '1237', 'l', '369', '6627', '3521', '5265']
answer:

a, d, e, g, h, l, p, r, w, y, z