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:
['k', 'r', 'f', '4369', 'z', 'z', 'l', '143', 'r', '707', '9167', 'g', '1749', 'i']
answer:
f, g, i, k, l, r, z


question:
['4749', '4607', '625', '6907', 't', 'b', '8479', '6505', 'r']
answer:
b, r, t


question:
['455', 'b', 'j', '51', 'w', '1403', '1433', '2795', '5851', 'r', '673', 'd', 'd', 't', 'w', '683', 'w', 'k', 'd', 'k', 'b', '609', 'a', '3099', 'g', '8707', '3615', '6189', 'y', 'i', '611', 'w', '6045', '1353', '7527', 'd', '8969', '8213', 'a']
answer:

a, b, d, g, i, j, k, r, t, w, y