import java.io.*;
import java.util.*;
/*
Составить цепочку слов
*/
public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader( System.in));
        String s = reader.readLine();
        reader = new BufferedReader(new FileReader(s));
        StringBuilder sb = new StringBuilder();
        while(reader.ready())
        {
            sb.append(reader.readLine());
            sb.append(" ");
        }
        reader.close();

        //...
        StringBuilder result = getLine(sb.toString().split(" "));
        System.out.println(result.toString());
    }


    public static StringBuilder getLine(String... words) {
        if(words.length==0){return new StringBuilder();}
        HashMap<Integer,StringBuilder> lines = new HashMap<>();

        for(int i = 0; i< words.length; i++){
            StringBuilder builder = new StringBuilder(words[i]);
            builder.append(" ");
            ArrayList<String> secondlist = new ArrayList<>(Arrays.asList(words));;
            for(int j = 0; j<secondlist.size(); j++){
                if(words[i].equals(secondlist.get(j))){
                    secondlist.remove(j);
                    j--;
                    continue;
                }
                char[] wholeline = builder.toString().toLowerCase().toCharArray();
                char[] word = secondlist.get(j).toLowerCase().toCharArray();
                if( wholeline[wholeline.length-2] == word[0]){
                    builder.append(secondlist.get(j));
                    builder.append(" ");
                    secondlist.remove(j);
                    j = 0;
                }
            }
            builder.deleteCharAt(builder.length()-1);
            lines.put(builder.length(), builder);
        }

        int key = 0;

        for(Map.Entry<Integer, StringBuilder> i : lines.entrySet()){
            if(key< i.getKey()){
                key= i.getKey();
            }
        }

       return lines.get(key);

    }

}
package com.javarush.task.task22.task2209;