import java.io.*;
import java.net.*;

public class Router{
	public static void main(String args[])throws Exception
	
	{
	
		String clientSentence;
	
		String modifiedSentence;
	
		ServerSocket welcomeSocket = new ServerSocket (4000);
		
		double y;
	
		while(true){    
		             System.out.println("Router listening!");
	
			     Socket connectionSocket = welcomeSocket.accept();
				
			     BufferedReader inFromClient = new BufferedReader(new InputStreamReader(
				                                                    connectionSocket.getInputStream()));
						
			     clientSentence = inFromClient.readLine();
			     System.out.println(clientSentence);
						
		             DataOutputStream outToClient =new DataOutputStream(
			  	        								  connectionSocket.getOutputStream());
	                     y=Math.random()*100+1;
			     if(y>50)
			        outToClient.writeBytes("UAK"+'\n');
						
			     if(y<=50)
				{
					outToClient.writeBytes("ACK"+'\n');
					Socket clientSocket = new Socket("127.0.0.1",8000);
						
					DataOutputStream outToServer = new DataOutputStream (
				  	    
				  	clientSocket.getOutputStream());
				  	BufferedReader inFromServer = new BufferedReader (new InputStreamReader (
	       												      clientSocket.getInputStream()));            
				  	outToServer.writeBytes(clientSentence + '\n');
				  	System.out.println(clientSentence+"send to 8000");
				  	modifiedSentence = inFromServer.readLine();
				  	
				  	
				
				}
			      else System.out.println(clientSentence+"dropped!");
						
			        	                	
			}

	}

}