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:
['6627', '8037', 'q', 'e', 'j', 'p', '9613', '9317', 'm', 'm', '5345', 'f', '8105', '5665', '4175', '4793', '3707', 'i', 'b', '6745', '747', '8329', '1481', 'b', '8949', 'n', '4803', '1359', '3533', 'f', '543', '3003', '6943']
answer:
b, e, f, i, j, m, n, p, q


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:
['1731', 'q', 'r', '3227', 'm', '7413', '9713', 'd', 'e', 'l', 'e', 'b', 'v', '8625', 'm', 'k', '6543', 'i', '7561']
answer:

b, d, e, i, k, l, m, q, r, v