import java.io.; import java.util.;

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 sc = new Scanner(System.in);
    String str = sc.nextLine();
    int k = sc.nextInt();
    System.out.println(smallestSubString(str,k)+"\n"+largestSubString(str,k));
}
static String smallestSubString(String str,int k)
{
    List<String> list = getSubStrings(str,k);
    //int len = list.length;
    return list.get(0);
}
static String largestSubString(String str,int k)
{
    List<String> list = getSubStrings(str,k);
    int len = list.size();
    return list.get(len-1);
}
static List<String> getSubStrings(String str, int k)
{
    List<String> subStr = new ArrayList<String>();
    int l = str.length();
    for(int i=0;i<l;i++)
    {
        String sub = "";
        boolean flag = false;
        for(int j=i;j<i+k;j++)
        {
            if(j>=l)
            {
                //subStr.add(sub);
                flag = true;
                break;
            }
            else
            {
                 sub+=str.charAt(j);  
            }
        }
        if(flag)
        {
            break;
        }
        subStr.add(sub);
    }
    Collections.sort(subStr);
    return subStr;
}

}