Default_Values

import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class p02_Default_Values {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String inputLine = scanner.nextLine();

        LinkedHashMap<String, String> keyValuePairs = new LinkedHashMap<>();

        while (!"end".equals(inputLine)) {
            String[] tokens = inputLine.split(" -> ");
            String key = tokens[0];
            String value = tokens[1];

            keyValuePairs.put(key, value);

            inputLine = scanner.nextLine();
        }

        inputLine = scanner.nextLine();

        for (Map.Entry<String, String> keyValuesEntry : keyValuePairs.entrySet()) {
            String k = keyValuesEntry.getKey();
            String v = keyValuesEntry.getValue();
            if ("null".equals(v)) {
                keyValuePairs.put(k, inputLine);
            }
        }

        Stream<Map.Entry<String, String>> orderedKeyValues = keyValuePairs.entrySet().stream()
                .sorted((a, b) -> a.getValue().compareTo(b.getValue()));

        for (Map.Entry<String,String> keyValuesOrdered : orderedKeyValues.collect(Collectors.toList())) {
            String key = keyValuesOrdered.getKey();
            String value = keyValuesOrdered.getValue();

            System.out.printf("%s <-> %s\n", key, value);
        }
    }
}