package com.javarush.task.task08.task0829;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;

/*
Модернизация ПО
*/

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        Map<String, String> map = new HashMap<>();

        while (true) {
            String lastName = reader.readLine();
            String city = reader.readLine();
            if (lastName.isEmpty() || city.isEmpty()){
                break;
            }
            map.put(lastName, city);
        }

        String nowCity = reader.readLine();

        Iterator<Map.Entry<String, String>> iterator = map.entrySet().iterator();

        while (iterator.hasNext()){
            Map.Entry<String, String> pair = iterator.next();
            if (pair.getValue().equals(nowCity)){
                System.out.println(pair.getKey());
            }
        }
    }
}