import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.FileReader;
import java.io.IOException;


public class CatFiles
{

    public static void main(String[] args)
    {

            BufferedReader r = null;
            BufferedWriter w = null;
            int n = args.length;
            int m = n - 1;
            try
            {
                w = new BufferedWriter(new FileWriter(args[m]));
            }
            catch (IOException e)
            {
                System.out.println("cannot write file");
            }

            for (int i = 0; i < n; i++)
            {
                try
                {
                    r = new BufferedReader(new FileReader(args[i]));
                }
                catch (FileNotFoundException e)
                {
                    System.out.println("file not found");
                }

                try
                {
                    String line = r.readLine();
                    while(line != null)
                    {
                        w.write(line);
                        r.readLine();
                    }
                }
                catch (IOException e)
                {
                    System.out.println("cannot write this file");
                }
                try
                {
                    r.close();
                }
                catch (IOException e)
                {
                    System.out.println("cannot close reader");
                }

            }

            try
            {
                w.close();
            }
            catch (IOException e)
            {
                System.out.println("cannot close writer");
            }

    }

}