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:
['8527', 'p', '4697', '8415', 'v', 'l', '2669', '2649', '4349', '4201', 'r', '7573', '2041', 'f', '8047', 'u', 'm', 'm', 'j', '5695']
answer:
f, j, l, m, p, r, u, v


question:
['b', 'd', '8153', 'u', '3695', '5317']
answer:
b, d, u


question:
['8299', '7355', '909', 'q', 'y', '2257', 'p']
answer:

p, q, y