import java.io.*;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.FilenameFilter;
import java.io.File;
import java.lang.*;
 
class FileWriteDemo
{
  public static void main(String args[])throws IOException
  {
	FileReader fr = new FileReader("file3.txt");
	BufferedReader br = new BufferedReader(fr);
	String s;
	StringBuffer sr =new StringBuffer(br);
	while(sr=br.readLine())!= null)
	{
 
		if(sr=="hi")
                 {
		   sr.delete(0,100);
		 }
       } 
 
 
   FileWriter f1= new FileWriter("file4.txt");
   String str1=sr.toString();
   f1.write(str1);
   f1.close();
  }
}