import java.io.*;
import java.util.*;

public class Concatenate {
    public static void main(String[] args) throws IOException {
    	Vector<String> listOfFileNames = new Vector<String>();
    	String nextFileName;
    	Scanner stdin = new Scanner(System.in);
    	BufferedWriter outFile;
  
    	nextFileName = stdin.next();
        outFile = new BufferedWriter(new PrintWriter(nextFileName));
        
    	while(stdin.hasNext()) {
    		nextFileName = stdin.next();
    		listOfFileNames.add(nextFileName);
    	}
    	
    	String [] fileNames = new String[listOfFileNames.size()];
    	listOfFileNames.toArray(fileNames);
    	
    	ListOfFiles listOfFiles = new ListOfFiles(fileNames);

        SequenceInputStream s = new SequenceInputStream(listOfFiles);
        InputStreamReader r = new InputStreamReader(s);
        
        int c;
        while ((c = r.read()) != -1)
           outFile.write(c);

        r.close();
        outFile.flush();
        outFile.close();
    }
}