import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * @author 令照辉 [zeekling@163.com]
 * @version 1.0
 * @apiNote
 * @since 2020-03-01
 */
public class BrotherWord {


    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String s = null;
        while ((s = br.readLine()) != null) {
            String[] vals = s.split(" ");
            if (vals.length < 4)
                continue;
            int num = Integer.parseInt(vals[0]);
            if (num > 1000)
                continue;
            String key = vals[num + 1];
            int index = Integer.parseInt(vals[num + 2]);
            List<String> list = new ArrayList<String>();
            for (int i = 1; i <= num; i++) {
                if (isBrothStr(vals[i], key))
                    list.add(vals[i]);
            }
            Collections.sort(list);
            System.out.println(list.size());
            if (list.size() >= index)
                System.out.println(list.get(index - 1));
        }
    }

    private static boolean isBrothStr(String source, String dest) {
        if (source.equals(dest) || source.length() != dest.length())
            return false;
        for (int i = 'a'; i <= 'z'; i++) {
            char ch = (char) i;
            if (getCharSize(source, ch) != getCharSize(dest, ch))
                return false;
        }
        return true;
    }

    private static int getCharSize(String source, char ch) {
        int count = 0;
        for (int i = 0; i < source.length(); i++)
            if (source.charAt(i) == ch)
                count++;
        return count;
    }

}