package strings;

//Given a string, find out the lexicographically smallest and largest substring of length .

//

//Input Format

//

//First line will consist a string containing english alphabets which has at most characters. 2nd line will consist an integer .

//

//Output Format

//

//In the first line print the lexicographically minimum substring.

//In the second line print the lexicographically maximum substring.

//Sample Input

//

//welcometojava

//3

//Sample Output

//

//ava

//wel

//Explanation

//Here is the list of all substrings of length 3:

//

//wel

//elc

//lco

//com

//ome

//met

//eto

//toj

//oja

//jav

//ava

import java.io.*;

import java.util.*;

import java.text.*;

import java.math.*;

import java.util.regex.*;

public class Solution {

public static void main(String[] args) {

/* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */

Scanner input = new Scanner(System.in);

String s;

int subLength;

s=input.nextLine();

subLength=Integer.parseInt(input.nextLine());

input.close();

int iterations = s.length()-subLength;

String largest = s.substring(0,subLength);

String smallest = s.substring(0,subLength);

for(int i = 0; i<=iterations;i++)

{

if(largest.compareTo(s.substring(i,i+subLength))<0)

{

largest = s.substring(i,i+subLength);

}

if(smallest.compareTo(s.substring(i,i+subLength))>0)

{

smallest = s.substring(i,i+subLength);

}

}

System.out.println(smallest);

System.out.println(largest);

}

}