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:
['d', '5285', 'z', 't', 'i', '719', 'z', 'b', '3603', '4781', 'o', 'g', 'j', 'd', 'r', 'a', 'x', '5829', '4907', '7395', '993', '2109', '1745', '415', '7525', '1029', '7791', '5321', 'h', '6391', 'g', '4613', '9191', 'o', '7365', '1811', '9695', 'w']
answer:
a, b, d, g, h, i, j, o, r, t, w, x, z


question:
['7071', 'h', '837', 'z', 'c', '2217', 'c', '6341', '6607', 'g', '3569', 'a', 'h', 't', 'b', 'f', 'g', 'f', 'l', 'b', 'x', 'o', 'r', '8949', '8071', '1507', 'v']
answer:
a, b, c, f, g, h, l, o, r, t, v, x, z


question:
['9873', '8665', '9761', 'n', '9597', '2721', '3197', '3975', 'p', '9745', '6333', 'p', '6181', 'i', 'v', 'd', 's', '381', '7397', 't', 'h', '9625', '8707', 'g']
answer:

d, g, h, i, n, p, s, t, v