Scanner scan = new Scanner(System.in); String s = scan.nextLine(); int k = Integer.parseInt(scan.nextLine()); int N = s.length()-(k-1); String[] arr = new String[N]; for(int i=0;i

import java.util.Scanner;

public class Solution { static String getSmallestAndLargest(String s, int k) { String smallest = s.substring(0,k); String largest = s.substring(0,k); for(int i=1;i<=s.length()-k;i++){ String sub = s.substring(i,i+k); int d = smallest.compareTo(sub); if(d>0) smallest = sub; String new_sub = s.substring(i,i+k); int p = largest.compareTo(new_sub); if(p<0) largest = new_sub;

      }

    // Complete the function
    // 'smallest' must be the lexicographically smallest substring of length 'k'
    // 'largest' must be the lexicographically largest substring of length 'k'

    return smallest+"\n"+largest;
}



public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    String s = scan.next();
    int k = scan.nextInt();
    scan.close();

    System.out.println(getSmallestAndLargest(s, k));
}

}

public static String getSmallestAndLargest(String s, int k) {
    String smallest = "";
    String largest = "";

    // Complete the function
    // 'smallest' must be the lexicographically smallest substring of length 'k'
    // 'largest' must be the lexicographically largest substring of length 'k'
    java.util.ArrayList<String> substr = new java.util.ArrayList<>(); // Empty list
    int i=0;

    while(i+k<=s.length()){
    substr.add(s.substring(i, i+k));
    i++;
    }
     java.util.Collections.sort(substr);
    smallest = substr.get(0);
    largest = substr.get(substr.size()-1);
    return smallest + "\n" + largest;
}

public static String getSmallestAndLargest(String s, int k) {

    String smallest = s.substring(0, k);
    String largest = smallest;

    for (int x=1; x<=s.length()-k; x++) {

        String tempSub = s.substring(x, x+k);

        smallest = (tempSub.compareTo(smallest)<0) ? tempSub : smallest;
        largest = (tempSub.compareTo(largest)>0) ? tempSub : largest;
    }
    return smallest + "\n" + largest;
}

import java.io.; import java.util.; import java.util.stream.*;

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. */

    try(Scanner s = new Scanner(System.in)){
        //System.out.println("Enter your string");
        String str = s.next();
        //System.out.println("Enter Sub String size or length");
         int len = s.nextInt();

      System.out.println(getSmallestAndLargest(str, len));

    }
}

public static String getSmallestAndLargest(final String str, final int l){
    if(Objects.isNull(str) || str.isBlank() || str.length()< l  || l<=0 || str.length()>1000){
        return "";
    }
   List<String> s = IntStream.range(0, str.length()-l+1)
    .mapToObj(i-> str.substring(i, i+l))
    .map(String::trim)
    .distinct()
    .sorted()
    .collect(Collectors.toList());

    if(s.size() >2){
       return String.format("%s"+"\n"+"%s", s.get(0), s.get(s.size()-1)); 
    }


    if(s.size() ==1){
       return String.format("%s"+"\n"+"%s", s.get(0), s.get(0)); 
    }

    return "";
}

}