import java.io.IOException;
import  java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import  java.net.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class network {
        public  static   String  getCharset(BufferedReader in){
        Pattern  Pname=Pattern.compile("charset=(\\w*)\\p{Punct}*",Pattern.UNIX_LINES);
         Matcher  Mk  =null;
           String    name=null;
          
          try{  
              for(int jk=0 ; jk<4 ; jk++){    
                  for(int i=0 ; i<4 ; i++)  name=in.readLine();
                  Mk   =Pname.matcher(name); 
                  if(Mk.find()) break;
               }
             return   Mk.group(1) ;  
          }catch(IllegalStateException e){
                return null;
           }catch( IOException e){
               return null;
            }finally{  
                try {
                  if(in != null)    in.close();
                } catch (IOException e) {
                    return null;
                }
             }
          
          
   }
     
  
}