It will be enabled in 10-20 minutes.

Never

Not sure this is the problem, but instead of

public static String dir=System.getProperty("user.dir");
...
Scanner sc=new Scanner(new File(dir+"/input.txt"));
...
File f=new File(dir+"/output.txt");

you should write

Scanner sc=new Scanner(new File("input.txt"));
...
File f=new File("output.txt");

Fixed :)

Try now.

Fixed.