class output 
    {
        public static void main(String args[])
        { 
           String c = "  Hello World  ";
           String s = c.trim();
           System.out.println("\""+s+"\"");
        }
    }

    class output 
    {
        public static void main(String args[])
        { 
           String s1 = "Hello";
           String s2 = s1.replace('l','w');
           System.out.println(s2);
        }
    }

    class output 
    {
        public static void main(String args[])
        {
           String s1 = "Hello World";
           String s2 = s1.substring(0 , 4);
           System.out.println(s2);
        }
   }

    class output 
    {
        public static void main(String args[])
        {             String s = "Hello World";
             int i = s.indexOf('o');
             int j = s.lastIndexOf('l');
             System.out.print(i + " " + j);
 
        }
   }