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:
['3043', 'r', 'm', 'i', '2653', 'i', '1703', '1125', '6299', '4863', 'n', 'h']
answer:
h, i, m, n, r


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


question:
['6201', 'a', 'u', 'h', '7305', 't', '253', '5139', '687', 't', 'y', 'm']
answer:

a, h, m, t, u, y