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:
['5089', '6113', 'v', 'l', '5529', 'q', '7499', 'e', 'r', 'c', '5999', '2619', 'a', '2523', '7697', 'j', 'c', '6537', '8313', '5623', '4225', '7677', 'q', 'a', '6559', 'y', 'b', 'm', '7645', '7019', 'r', 'i', '5225', '703', 'i', '6189', 'f', 't', '7553']
answer:
a, b, c, e, f, i, j, l, m, q, r, t, v, y


question:
['4993', 'n', '7115', 'f', 'd', 'q', '249', '3203', 'w', '5689', '4103', '7129', '603', 'e', 'z', '5571', '3241', '6029', '2721', '8451', 'o', '7841', 'p', '6271', 'r', 'b', '9481', '4045', 'v']
answer:
b, d, e, f, n, o, p, q, r, v, w, z


question:
['p', 'm', 'e', 'i', '59', '6485', '363', 'm', '5889', 'c', 'f', '1309', '8423', '2959', 'h', '2115', 'c', '5093', '9625', '2459', 'i', '9325', 't', 'x', 'f', '8735', 'r', '2499']
answer:

c, e, f, h, i, m, p, r, t, x