import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String line = sc.nextLine();
        String[] strings = line.split(" ");
        int n = Integer.parseInt(strings[0]);
        int k = Integer.parseInt(strings[strings.length - 1]);
        String x = strings[strings.length - 2];
        char[] xChar = x.toCharArray();
        Arrays.sort(xChar);
        String xNew = new String(xChar);
        ArrayList<String> list = new ArrayList<>();
        for (int i = 1; i < 1 + n; i++) {
            String temp = strings[i];
            if (temp.equals(x)) {
                continue;
            }
            char[] tempChar = temp.toCharArray();
            Arrays.sort(tempChar);
//            System.out.println("此时:"+xNew+";"+new String(tempChar));
            if (xNew.equals(new String(tempChar))) {
                list.add(temp);
            }
        }
        list.sort(new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return o1.compareTo(o2);
            }
        });
        System.out.println(list.size());
        if (k <= list.size()) {
            System.out.println(list.get(k - 1));
        }
    }
}