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

public class Server{
 
 public static void main(String[] args) throws Exception{
  ServerSocket mysock = new ServerSocket(1234);
  
  Socket mylink = mysock.accept();
  System.out.println("new client connected");
  
  DataInputStream input = new DataInputStream(mylink.getInputStream());
  DataOutputStream output = new DataOutputStream(mylink.getOutputStream());
  
  String request="";
                String temp=null;
  String sendstring="";
  String cipher="";
                String plaintext="";
  Scanner inp = new Scanner(System.in);
  
  while(!request.equals("QUIT")){
   request=input.readUTF();
   plaintext=decipherCaesar(request);
   System.out.println("cipher:"+request);
                        System.out.println("plaintext:"+plaintext);
                        
   
                        temp=inp.next();
                        
                        sendstring=caesarCipher(temp);
   
                        output.writeUTF(sendstring);
      
  }
  
  mylink.close();
  
 }
 
 
 public static String caesarCipher(String x){
      String temp = "";
      x = x.trim(); //remove whitespace
      x = x.toLowerCase(); //In java, 'A' != 'a', so we want the letters in one case

   //This section establishes the alphabet in an ArrayList.
      ArrayList<Character> reference = new ArrayList<Character>();
      for(char i = 'a'; i <= 'a' + 25; i++) reference.add(i);

   //This section handles the encryption
      for(int i = 0; i < x.length(); i++){

     //Checks to see if the character is a letter
          if(!Character.isLetter(x.charAt(i))) temp += x.charAt(i);
          else{temp += reference.get((reference.indexOf(x.charAt(i)) + 3)&);}
          
          }
      return temp;
 }
        
        public static String decipherCaesar(String x){
      String temp = "";
      x = x.trim(); //remove whitespace
      x = x.toLowerCase(); //In java, 'A' != 'a', so we want the letters in one case

   //This section establishes the alphabet in an ArrayList.
      ArrayList<Character> reference = new ArrayList<Character>();
      for(char i = 'a'; i <= 'a' + 25; i++) reference.add(i);

   //This section handles the encryption
      for(int i = 0; i < x.length(); i++){

     //Checks to see if the character is a letter
          if(!Character.isLetter(x.charAt(i))) temp += x.charAt(i);
          else{temp += reference.get((reference.indexOf(x.charAt(i)) + 23)&);}
          
          }
      return temp;
 }
        
        public static String cipher2(String y){
            String plaintext=y;
            String ciphertext=null;
            char chars[] = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
        
        
            
                char[] plain = plaintext.toLowerCase().toCharArray();
                
                for(int i = 0;i<plain.length;i++){
                    for(int j = 0 ; j<26;j++){
                        if(j<=22){
                            if(plain[i]==chars[j]){
                                plain[i] = chars[j+3];
                                break;
 
                            }  
                        }//End nested If
                            else if(plain[i] == chars[j]){
                                plain[i] = chars [j-23];
                            }  //End else
                    } //End nested for loop
                } //End of For loop
                
                
                ciphertext = String.valueOf(plain);
            
            
            return ciphertext;
                
            }
        
        public static String decipher2(String y){
            String ciphertext=y;
            String plaintext=null;
            char chars[] = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
        
        
            
                char[] cipher = ciphertext.toLowerCase().toCharArray();
                
                for(int i = 0;i<cipher.length;i++){
                            for(int j = 0 ; j<26;j++){
                                if(j>=3 && cipher[i]==chars[j]){
                                    cipher[i] = chars[j-3];
                                    break;
                                }
                                    if(cipher[i] == chars[j] && j<3){
                                        System.out.println("Replacing "+cipher[i]+" by "+chars[23+j]+" "+j+23+"");
                                        cipher[i] = chars[23+j];
                                        break;
                          }  //End IF
                    } //End nested for loop
                } //End of For loop
                
                
                plaintext = String.valueOf(cipher);
            
            
            return plaintext;
                
            }
}