BufferedReader b = new BufferedReader(new InputStreamReader(System.in));
        ArrayList<String> s = new ArrayList<String>();
        for(int a=0; a<10; a++)
        {
            s.add(b.readLine());
        }

        ArrayList<String> result = doubleValues(s);


         for( String x: result)
         {
             System.out.print(x +" -> "+ x +" , ");
         }
        // Display result
    }

    public static ArrayList<String> doubleValues(ArrayList<String> s) {
        //write your code here
        //int ss = s.size();
        for(int i=0; i<s.size(); i++)
        {
            s.add(i+1, s.get(i));
        }
        return s;
    }