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:
['3627', '2051', '3203', 'c', 'r', 'a', '1453', 'e', 'z', 't', '1093', '4651', 'a', 'f', '8159', '9623', 'l', 't', 'r', '6963', '7071', '8103', '3493', 'y', '2369', '609', '2011', 'f', '187', 'f', 'c']
answer:
a, c, e, f, l, r, t, y, z


question:
['o', 'l', 'm', 't', '4487', '1019', '9903', 'c']
answer:
c, l, m, o, t


question:
['b', 'r', '9335', 'f', 'l', 'z', '1203', 'm', '637', '9653', 'c']
answer:

b, c, f, l, m, r, z