public static String insertInSpecialPosition(String s, String s1, int position) {
        if(s.isEmpty()) {
            return s1;
        } else {
            StringBuilder sb = new StringBuilder();
            sb.append(s.substring(0,position));
            sb.append(s1);
            if(s.length()>position) {
                sb.append(s.substring(position));
            }
            return sb.toString();
        }
    }