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:
['t', 'a', '2481', '2841', 'a', '2871', 'm', '4435', 'g', '8201', '4351', '9045', 'o']
answer:
a, g, m, o, t


question:
['4925', 'i', 'q', 'k', '7615', 'r', '7217', 'o', '8097', '9151']
answer:
i, k, o, q, r


question:
['5525', '9787', 'w', 'y', '2225', '4171', '2957', '4275', '8249', '8803', '3895', 't', 'g', 'h', 'w', 'w', 'v', 'u', 'w', 'k', 'z', '3231', 'k', 'x', 'g', 'l', '6237', '9603', '8021', '81', '6019', 'z', 'j']
answer:

g, h, j, k, l, t, u, v, w, x, y, z