import java.io.*;

class Streamer extends Thread {
  
  /* Helper thread that passes every line of a Reader stream to output */

  String stream_name;
  BufferedReader str;

  public Streamer(BufferedReader s, String name) {
    str = s;
    stream_name = name;
  }

  public void run() {
    try {
      while (true) {
        String line = str.readLine();
	if (line==null) break;
	System.out.println(line);
      }

      System.out.println(stream_name + " terminated");

    } catch (Exception e) { System.out.println("Exception: " + e);}
  }
}


public class MemRelay {

    public static void main(String[] argv) {
	try {
	    
	    Runtime rt = Runtime.getRuntime();
	    Process w = rt.exec("./writer");
	    Process r = rt.exec("./reader");
	    
	    BufferedReader  in = 
		new BufferedReader(new InputStreamReader(System.in));

	    BufferedReader  w_input  = 
		new BufferedReader(new InputStreamReader(w.getInputStream())) ;
	    BufferedReader  w_error  = 
		new BufferedReader(new InputStreamReader(w.getErrorStream())) ;
	    PrintWriter w_output = new PrintWriter(w.getOutputStream());
	    
	    BufferedReader  r_input  = 
		new BufferedReader(new InputStreamReader(r.getInputStream())) ;
	    BufferedReader  r_error  = 
		new BufferedReader(new InputStreamReader(r.getErrorStream())) ;
	    PrintWriter r_output = new PrintWriter(r.getOutputStream());
	    
	    // Stream error channels to output
	    Streamer s_w = new Streamer(w_error,"Writer ");
	    Streamer s_r = new Streamer(r_error,"Reader ");
	    s_w.start();
	    s_r.start();

	    Thread.sleep(500);  // Give way for messages on error channels

	    try {
	        while (true) {
		    System.out.print("> ");
		    String line = in.readLine();
		    if (line==null) break;
		    
		    // Send line to writer
		    w_output.println("<" + line + ">");
		    w_output.flush();
		    
		    // Await that line has been passed to memory
		    String answer = w_input.readLine();
		    if (answer==null || !answer.equals("OK")) break;

		    // Pass on OK-signal to reader
		    r_output.println(answer);
		    r_output.flush();
		    
		    // Await reader to send line
		    String newline = r_input.readLine();  
		    if (newline==null) break;

		    System.out.println("* " + newline);
		}

		w_output.close();
		r_output.close();

	    } catch (IOException ioe) {}

	    System.out.println("Exit value writer= " + w.waitFor());
	    System.out.println("Exit value reader= " + r.waitFor());

	} catch (Exception e) { System.out.println("Exception: " + e);}

    }
}