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:
['8495', 'p', 'j', 'm', 'n', '9115', '1183', 'r', 'r', '8735', 'a', 'i', 'k', 'p', '8927', 'r', '9283', '9563', 'g', '2503', 'h', '1091', '5257', 'a', '3061', '2835', 'l', 'w', 'j', '7617', '8793', '7463', 'h', '8467', '7337', 'b', '4655', 'd']
answer:
a, b, d, g, h, i, j, k, l, m, n, p, r, w


question:
['6181', 'w', '4663', '5507', 'a', '6607', '869', '2669', 'r', '3629', 'r', 'l', '6599', '8885', 's', '4315', 'z', 'l', 'r', '1225', '8371', '1545', '7169', '1175', 'k', 'p', 'y', '7263', '5537', '8649', '3317', 'q', 'r', 'u', 'd', '4647', 'u', 'y', 'h', '9753', 'q', '725']
answer:
a, d, h, k, l, p, q, r, s, u, w, y, z


question:
['d', '4809', 't', 'b', 'c', '3233', 'p', 'v', 'a', 'a', 'h', '6001', 'y', 'o', '7365', '4343', '7153', 'x', 'u', 'c', '6743', '9609', '1727', 'd', 'h', '1391', 'k', '6629', '3367']
answer:

a, b, c, d, h, k, o, p, t, u, v, x, y