Write python program that inputs a text file. The program should print the unique words in the file in alphabetical order. Uppercase words should take precedence over lowercase words. For example, 'Z' comes before 'a'.

The input file can contain one or more sentences, or be a multiline list of words.

An example input file is shown below:

example.txt

the quick brown fox jumps over the lazy dog

An example of the program's output is shown below:

Enter the input file name: example.txt brown dog fox jumps lazy over quick the