public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        String s = sc.nextLine();
        int k = sc.nextInt();
        String smallest = "";
        String largest = "";
        
        sc.close();
        
        ArrayList<String> arrayList = new ArrayList<>();

        for (int i = 0; i < s.length(); i++) {

            if ((i + k) <= s.length()) {
                arrayList.add(s.substring(i, i + k));
            }
        }

        smallest = Collections.min(arrayList);
        largest = Collections.max(arrayList);

        System.out.println(smallest + "\n" + largest);
    }