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:
['6643', '6757', 'h', '1033', 's', 'c', '2003', 'p', '5483', 'f']
answer:
c, f, h, p, s


question:
['163', 'x', 'g', '5997', 'm', 'l', '7225', '7907', '375', 'y', 'a', 'j', 'c', 'j', '7755', '147', 'h', '3845', 'y', 's', 'h', 'u', '8737', '6091', 'j', 'f', 'c', '7395', '881', '1771', 'y', '3691', 'h']
answer:
a, c, f, g, h, j, l, m, s, u, x, y


question:
['25', 'h']
answer:

h