import java.util.Random;
import java.util.StringTokenizer;
import java.io.*;

public class DirtyWords 
  {
  public static void main(String[] args)
    {
    Random r = new Random();
    try  // We need try-catch because of potential problems with the files.
      {
      /* 
       * We create a BufferedReader from the filename which is the first
       * first command-line argument.
       */
      BufferedReader inputReader = new BufferedReader(new FileReader(args[0]));

      /* 
       * We create a PrintWriter from the filename which is the second
       * command-line argument.
       */
      PrintWriter outputWriter = new PrintWriter(new FileWriter(args[1]));

     /* The following while loop reads from the file line-by-line.  */
      boolean moreInput = true; 
      String oneLine;
      while (moreInput) 
        {
        oneLine = inputReader.readLine(); // Read a line from the file.
        if (oneLine == null)
 	  {
	  moreInput = false;
	  }
        else
          {
          StringTokenizer wordGetter = new StringTokenizer(oneLine);

	  /* 
	   * The following while loop reads individual words from a string 
	   * and copies them word-by-word to the output file.
	   */
          while (wordGetter.hasMoreTokens())
	    {
            String aWord = wordGetter.nextToken(); 
	    if (aWord.length() == 4)
	      {
	      aWord = randomString(r, 4);
	      }
            outputWriter.print(aWord);
	    outputWriter.print(" ");
	    }
          outputWriter.println(); 
	  }
        } 

      /* Now we close the input and output files. */
      inputReader.close();
      outputWriter.close();
      } 
    catch(IOException anError)
      {
      anError.printStackTrace(); // Show the function call stack for debugging.
      }
    }
  
  public static String randomString(Random r, int n)
    {
    String s = "";
    for(int i = 1; i <= n; i++)
      {
      s += (char)('!' + r.nextInt(11));
      }
    return s;
    }
  }