//TCPCLIENT

import java.io.*;
import java.net.*;
class TCPclient
{
 public static void main(String args[])throws Exception
 {
  String sentence,modifiedsentence;
  BufferedReader infromuser=new BufferedReader(new InputStreamReader(System.in));
  Socket clientSocket=new Socket("localhost",6789);
  DataOutputStream ToServer =new DataOutputStream(clientSocket.getOutputStream());
  BufferedReader infromserver = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
  sentence=infromuser.readLine();
  ToServer.writeBytes(sentence+"\n");
  modifiedsentence=infromserver.readLine();
  System.out.println(modifiedsentence);
  clientSocket.close();
 }
}

//TCPSERVER


import java.net.*;
import java.io.*;
class TCPserver
{
 public static void main(String args[]) throws Exception
 {
  String clientsentance,capital;
  ServerSocket welcomesocket=new ServerSocket(6789);
  while(true)
  {
   Socket connectionsocket=welcomesocket.accept();
   System.out.println(" Connected");
   BufferedReader infromclient=new BufferedReader(new InputStreamReader(connectionsocket.getInputStream()));
   DataOutputStream outtoclient=new DataOutputStream(connectionsocket.getOutputStream());
   clientsentance=infromclient.readLine();
   System.out.println("From client:"+clientsentance);
   capital=clientsentance.toUpperCase();
   outtoclient.writeBytes("From server:"+capital+ '\n');
  }
 }
}