Unique Words Sorted

You are given a string consisting of words separated by spaces. Your task is to output a sequence of unique words (ignoring case), sorted in alphabetical order. Each word in the output should be in lowercase.

Note: The comparison should be case-insensitive, and the output must be printed to standard output.

For example, if the input is "Hello world hello", the correct output is "hello world".

If the input line is empty, simply output an empty line.

The sorting should follow the standard lexicographical order defined in \(\text{ASCII}\) or your language's default string comparison, after converting all words to lowercase.

inputFormat

The input consists of a single line containing words separated by one or more spaces. The input is read from standard input (stdin).

outputFormat

Output a single line containing the unique words sorted alphabetically (after converting them to lowercase), with a single space separating consecutive words. The output is printed to standard output (stdout).

Hello world hello

hello world