/*
 * set-01.cc    Standard Library, std:.set, exercise 1.
 */
#include <iostream>
#include <set>
#include <cctype>
#include <string>
#include <iterator>
using namespace std;

bool read_word(istream& is, string& word)
{
   bool found_word{ false };
   char c;

   while (is.get(c))
   {
      if (isalpha(c))
      {
	 word = tolower(c);  // also clears old content of word
	 found_word = true;
	 break;
      }
   }

   while (isalpha(is.peek()))
   { 
      word += tolower(is.get());
   }

   return found_word;
}

int main()
{
   set<string> list;
   string      word;

   while (read_word(cin, word))
   {
      list.insert(word);
   }

   copy(begin(list), end(list), ostream_iterator<string>(cout, "\n"));

   return 0;
}